A caste is a combined social system of occupation, endogamy, culture, social class, and political power. Caste should not be confused with class, in that members of a caste are deemed to be alike in function or culture, whereas not all members of a defined class may be so alike. Although Indian society is often now associated with the word "caste", it was first used by the Portuguese to describe inherited class status in their own European society. English caste is from Latin castus "pure, cut off, segregated", the participle of carere "to cut off". Application to Hindu social groups originates in the 17th century, via Portuguese casta "breed, race, caste".
Discrimination based on caste, as perceived by UNICEF, is prevalent mainly in parts of Asia (India, Sri Lanka, Bangladesh, Nepal, Japan) and Africa. UNICEF estimates that such perceived discrimination based on caste affects 250 million people worldwide.
The Indo-Europeans who settled Europe, Western Asia and the Indian Sub-Continent conceived their societies to be ordered (not divided) in a tripartite fashion, the three parts being castes . Castes came to be further divided, perhaps as a result of greater specialisation.
The 'classic' formulation of the caste system as largely described by Georges Dumézil was that of a priestly or religiously occupied caste, a warrior caste, and a worker caste. This caste system can be seen to be that which flourished on the Indian Sub-Continent and amongst the Italic peoples. However, an alternative version of the system developed later to supplant it, that of Nobles, Bourgeois and Peasants, the last two being a split of the original worker caste, and the warrior and priestly function being subsumed into all three castes to a degree. This alternative caste formulation may have existed side-by-side in proto-Indo-European society as the Edda does not seem to hold to the 'classic' formulation.
Examples of the Indo-European Castes:
Kings were born out of the warrior or noble class.
The revolutions in British America and France and then elsewhere directly challenged Indo-European culture and swept away the native caste system and replaced it with a system based on class. But it is noticeable that in many countries the class system then followed a tripartite division like the caste system: for example the upper, middle and lower class used in Britain and the Dreiklassen system in Germany.
Indian society has consisted since ancient times, of several thousands of tribal and occupational groups, castes or communities called Jāti. The phrase "Hindu Caste System" mixes up two different schemes - the Varna (class/group), theoretical scheme based on idealized Brahminical traditions and some medieval codes, and the Jāti system prevalent in Indian society since historical times.
Faced with a bewildering array of thousands of autonomous and hierarchically fluid communities (Jatis), the late 19th century British colonial administration decided to categorise and rank the entire Hindu population of India by placing each of the Jatis within the theoretical Varna scheme for the purposes of the decennial Census, and ostensibly for eventual administrative convenience. The 1901 Census was led by Herbert Hope Risley, an ICS officer with strong pet racial beliefs about the Indian population. Simultaneous with this first ever codification into secular law of Varna-based caste identities during the British empire, communities (Jatis) sought to place themselves on higher levels of Varna categories. On the other hand, most of the Jatis grouped into the lower caste categories rejected the Varna categories as they found this arbitrary classification unreasonable, unfair and unacceptable, as it did not reflect the reality. This newly frozen materialization of caste created a growing resentment firstly against the system itself and secondly against the Brahmins, who were seen to be the beneficiaries of the arrangement which now officially anointed their place at the top of the social hierarchy. The revolt of the Justice Party and Periyar in the south, by the Maharaja of Kolhapur and the outstanding scholar Dr Ambedkar in western India against this, in the early decades of the twentieth century, has had a profound, long-lasting impact on the Indian society and politics, which continues to this date.
The British Colonial melding of the ubiquitous and fluid Jati with the theoretical and rigid Varna scheme starting from the 1901 Census has resulted in many people erroneously assuming that the entire Hindu society was organized according to the Varna scheme since ancient times. In fact, India's diverse population viewed the artificially rigid scheme as unjust and arbitrary. Modern Indian society has struggled with this flawed, inflexible imposition of caste implemented by the British since the 1901 Census.
Some activists, most prominently at the UN conference at Durban, have asserted that the caste is a form of racial discrimination. This view has been disputed by some sociologists such as Andre Béteille, who writes that treating caste as a form of racism is "politically mischievous" and worse, "scientifically nonsense" since there is no discernible difference in the racial characteristics between Brahmins and Scheduled Castes such as the Jatav. He writes that "Every social group cannot be regarded as a race simply because we want to protect it against prejudice and discrimination."
The Indian government, too, has denied the claims of equivalence between caste and racial discrimination, pointing out that the issues of social status is essentially intra-racial and intra-cultural. The view of the caste system as "static and unchanging" has also been disputed. The Indian government has been working towards creating equality between castes with guaranteed seats in educational institutions, government jobs (and promotions) and even in the parliament for those of the Scheduled Untouchable castes and tribes. Scholarships have also been available to all of these groups, so that they can go on to further education more easily and this has raised their social status.Sociologists describe how the perception of the caste system as a static and textual stratification has given way to the perception of the caste system as a more processional, empirical and contextual stratification. Others have applied theoretical models to explain mobility and flexibility in the caste system in India. According to these scholars, groups of lower-caste individuals could seek to elevate the status of their caste by attempting to emulate the practices of higher castes. The eminent Socio-anthropologistM. N. Srinivas has also questioned the rigidity of caste and introduced the concept of Sanskritisation..
In any event, now in modern India, with rapid urbanization and large scale migration, the ensuing crowded living arrangements and public transport, and the broad-based mix of workplace colleagues, there has been a significant change in social attitudes, at least in the larger towns and certainly in the metros. Associations of occupations with caste have also been changing, especially as new occupations are developing.
Early Indian texts like the Manusmriti and the Puranas speak of 'Varna,' which means order, category, type, colour (of things), and groups the society into four main types as follows. Brahmins (scholar, teacher, priest) Kshatriyas (warrior, king), [Soldiers]) Vaishyas (merchant, agriculturist) Shudras (worker, service provider)
All others who did not subscribe to the norms of this Hindu society, including foreigners, tribals and nomads, or even those who had been excommunicated, were called Mlechhas or "Anaryas" and were to be treated as contagious and untouchables. The fear of banishment from the society was seen as a major disincentive against violating its norms by its members. A late section of the Shanti Parva of the Mahabharata suggests an origin of this practice: " He who becomes harsh in speech, or violent in temper, he who seduces or abducts other people's women or robs the wealth that belongs to others, should be cast off by us".
The Varna system being a Utopian scheme should however be differentiated from the ubiquitous socio-cultural Jati-caste-system pervasive throughout India since ancient times. According to the Varna system, Brahmins are enjoined to live in poverty and their primary vocation was to learn the Vedas, sacred texts and secular subjects, teach others and pray for the well-being of all. The Kshatriya's chief occupation was martial skills and kingship. The Vaishyas were those occupied with trade and agrarian activities including cattle raising, while the Sudras were workers and service providers of all types. All the Varnas were urged, without exception, to inculcate non-possessiveness, non-stealing, truthfulness, non-violence and benevolence. These too were the very attributes propounded by the Jain and Buddhist doctrines.
As the historian Romila Thapar has pointed out in her 'The Past and Prejudice': "The dynamic of Indian society was the juxtaposition of precept to practice, of the organisation of life as it should be, to the organisation of life as it is. For every aspect of life, from the most mundane to the most exhilarating, there was a theory of functioning which did not necessarily reflect the reality. The theory was the ideal image.....The resulting dichotomies were not forced into confrontation but were adjusted...Such adjustments seem easier in pre-industrial societies whose cultures invariably appear to be more gentle, meditative and less competitive,..".
It may also be noted that although Brahmins have usually been described as the priestly class, this is not entirely accurate, as a temple priest need not have been a Brahmin, in fact very few could have been, given the vast number of temples and the sparse population of Brahmins; however, the performers of a Vedic Yajna for others or a public Yajna fire sacrifice usually were Brahmins. All the Dvija (Twice Born) ie Brahmins, Kshatriyas and Vaishyas could and did perform the Homa fire sacrifice for themselves. Even this has not always been followed by all sects within Hinduism - for example, in the Arya Samaj, all castes including Shudras can perform the fire sacrifice. There were several categories among the Brahmins and temple priests were usually at the lower end of the Brahmin social scale. The ancient Greeks, e.g., Megasthenes in his Indika, and the Muslims, e.g. Alberuni (1030 CE) described Brahmins as philosophers. Megasthenes calls them Brachmanes and characterizes them thus:
"The philosophers are first in rank, but form the smallest class in point of number. Their services are employed privately by persons who wish to offer sacrifices or perform other sacred rites, and also publicly by the kings at what is called the Great Synod, wherein at the beginning of the new year all the philosophers are gathered together before the king at the gates, when any philosopher who may have committed any useful suggestion to writing, or observed any means for improving the crops and the cattle, or for promoting the public interests, declares it publicly."
According to some researchers, by the 4th century AD, and certainly by the 7th century AD,  there were people excluded from society altogether - the group of outcastes now referred to by themselves as Dalits or the "downtrodden." Thus, an untouchable, or an "outcaste", was a person who was deemed to not have any "Varna by those who claimed to possess it."
Professor Madhav Gadgil (1983) has described the reality of castes, which are called Jatis, in India, based on his research in rural Maharashtra: "The Indian society is even today an agglomeration of numerous castes, tribes and religious communities. The tribal and caste groups are endogamous, reproductively isolated populations traditionally distributed over a restricted geographical range. The different caste populations, unlike tribes, have extensive geographical overlap and members of several castes generally constitute the complex village society. In such a village society, each caste, traditionally self regulated by a caste council, used to lead a relatively autonomous existence. Each caste used to pursue a hereditarily prescribed occupation; this was particularly true of the artisan and service castes and the pastoral and nomadic castes. The several castes were linked to each other through a traditionally determined barter of services and produce (Ghurye 1961, Karve 1961). These caste groups retained their identity even after conversion to Islam or Christianity. Each of the caste groups was thus the unit within which cultural and perhaps genetic evolution occurred, at least for the last 1500 years when the system was fully crystallized and probably much longer. Over this period the various castes had come to exhibit striking differences in cultural traits like skills possessed, food habits, dress, language, religious observances, as well as in a number of genetic traits." 
In "A New History of India," Stanley Wolpert states," a process of expansion, settled agricultural production, and pluralistic integration of new people led to the development of India's uniquely complex system of social organization by occupation...."
Under the Jati system, a person is born into a Jati with ascribed social roles and endogamy, i.e. marriages take place only within that Jati. The Jati provided identity, security and status and has historically been open to change based on economic, social and political influences (see Sanskritization). In the course of early Indian history, various tribal, economic, political and social factors led to a continuous closing, consolidation and variation in the prevailing social ranks which tended to become traditional, hereditary system of social structuring. This system of thousands of exclusive, endogamous groups, is called Jāti. Though there were several kinds of variations across the breadth of India, the Jati was the effective community within which one married and spent most of one's personal life. Often it was the community (Jati) which one turned to for support, for resolution of disputes and it was also the community which one sought to promote.
The Untouchables - Pariahs or Antyajas, were at the bottom of the social scale and even now perform the jobs nobody else wants such as raw sewage handling, killing animals or execution of criminals; They lived in special areas and were not allowed to read holy books. It is, however, rather interesting that people of all Jatis across the spectrum, from the so-called upper castes to the lowest of castes, including the Untouchables, tended to avoid intermarriage, sharing of food and drinks, or even close social interaction with a Jati other than their own. Indeed, most of the Jati castes did not see themselves as socially inferior to the others in any way. If at all, it was the other way round and most of them had folk narratives, traditions, myths and legends to bolster their sense of identity and cultural uniqueness.
An interesting perspective on ancient North Indian society is provided by the Greek Megasthenes, who, in his Indika, described the society as being made up of "seven classes":
"The whole population of India is divided into seven classes, of which the first is formed by the collective body of the Philosophers, which in point of number is inferior to the other classes, but in point of dignity preeminent over all. For the philosophers, being exempted from all public duties, are neither the masters nor the servants of others. They are, however, engaged by private persons to offer the sacrifices due in lifetime, and to celebrate the obsequies of the dead: for they are believed to be most dear to the gods, and to be the most conversant with matters pertaining to Hades. In requital of such services they receive valuable gifts and privileges. To the people of India at large they also render great benefits, when, gathered together at the beginning of the year, they forewarn the assembled multitudes about droughts and wet weather, and also about propitious winds, and diseases, and other topics capable of profiting-the hearers. Thus the people and the sovereign, learning beforehand what is to happen, always make adequate provision against a coming deficiency, and never fail to prepare beforehand what will help in a time of need. The philosopher who errs in his predictions incurs no other penalty than obloquy, and he then observes silence for the rest of his life."
The other classes are also described by Arrian, in The Anabasis Alexandrae, Book VIII: Indica (2nd c. CE) relying on the account of Megasthenes:
"Then next to these come the farmers, these being the most numerous class of Indians; they have no use for warlike arms or warlike deeds, but they till the land; and they pay the taxes to the kings and to the cities, such as are self-governing; and if there is internal war among the Indians, they may not touch these workers, and not even devastate the land itself; but some are making war and slaying all comers, and others close by are peacefully ploughing or gathering the fruits or shaking down apples or harvesting.
The third class of Indians are the herdsmen, pasturers of sheep and cattle, and these dwell neither by cities nor in the villages. They are nomads and get their living on the hillsides, and they pay taxes from their animals; they hunt also birds and wild game in the country.
The fourth class is of artisans and shopkeepers; these are workers, and pay tribute from their works, save such as make weapons of war; these are paid by the community. In this class are the shipwrights and sailors, who navigate the rivers.
The fifth class of Indians is the soldiers' class, next after the farmers in number; these have the greatest freedom and the most spirit. They practise military pursuits only. Their weapons others forge for them, and again others provide horses; others too serve in the camps, those who groom their horses and polish their weapons, guide the elephants, and keep in order and drive the chariots. They themselves, when there is need of war, go to war, but in time of peace they make merry; and they receive so much pay from the community that they can easily from their pay support others.
The sixth class of Indians are those called overlookers. They oversee everything that goes on in the country or in the cities; and this they report to the King, where the Indians are governed by kings, or to the authorities, where they are independent. To these it is illegal to make any false report; nor was any Indian ever accused of such falsification.
The seventh class is those who deliberate about the community together with the King, or, in such cities as are self-governing, with the authorities. In number this class is small, but in wisdom and uprightness it bears the palm from all others; from this class are selected their governors, district governors, and deputies, custodians of the treasures, officers of army and navy, financial officers, and overseers of agricultural works.
To marry out of any class is unlawful -- as, for instance, into the farmer class from the artisans, or the other way; nor must the same man practise two pursuits; nor change from one class into another, as to turn farmer from shepherd, or shepherd from artisan. It is only permitted to join the wise men out of any class; for their business is not an easy one, but of all most laborious."
The Nepalese caste system resembles that of the Indian Jāti system with numerous Jāti divisions with a Varna system superimposed. But since the culture and the society is different some of the things are different. The caste system in Nepal was introduced by King Prithivi Narayan shah. He divided the caste system to make easy for division of work. He divided people into 4 caste and 36 verna.
In Pakistan, the tribes, clans and baradaris (Brotherhoods) follow social stratification especially in marriages. The concept of equality of humanity of Islam is tempered with clanish system. In the absence of "classical" castes, typically the proxies used are ethnic background (Sindhis, Punjabis, Pashtuns, Balochis, Muhajirs, etc.), Muslim sects (Sunnis, Shias, Ismailis, Bohras) and minority religions Qadyanis, Christianity, Hinduism.
Different dialects of the Balinese language are used to address members of a different caste. The Balinese caste system does not have untouchables. And there is mobility within the castes. So a family may have persons of all castes.
The Southern and Northern Dynasties showed such a high level of polarization between North and South that northerners and southerners referred to each other as barbarians. The Mongol Yuan Dynasty also made use of the concept; Yuan subjects were divided into four castes, with northern Han Chinese occupying the second-lowest caste and southern Han Chinese occupying the lowest one.
Traditional Yi society in Yunnan was caste based. People were split into the Black Yi (nobles, 5% of the population), White Yi (commoners), Ajia (33% of the Yi population) and the Xiaxi (10%). Ajia and Xiaxi were slave castes. The White Yi were not slaves but had no freedom of movement. The Black Yi were famous for their slave-raids on Han Chinese communities. After 1959, some 700,000 slaves were freed.
The two main castes in Japan were samurai and peasants. Only the samurai caste was allowed to bear arms. A samurai had a right to kill any peasant whom he felt was disrespectful.
Japan historically subscribed to a feudal caste system. While modern law has officially abolished the caste hierarchy, there are reports of discrimination against the Buraku or Burakumin undercastes, historically referred to by the insulting term Eta. Studies comparing the caste systems in India and Japan have been performed, with similar discriminations against the Burakumin as the Dalits. The Burakumin are regarded as "ostracised." The burakumin are one of the main minority groups in Japan, along with the Ainu of Hokkaidō and those of residents of Korean and Chinese descent.
The Baekjeong were an "untouchable" outcaste group of Korea, often compared with the burakumin of Japan and the dalits of India and Nepal. The term baekjeong itself means "a butcher," but later changed into "common citizens" to change the caste system so that the system would be without untouchables. In the early part of the Goryeo period (918 - 1392), the outcaste groups were largely settled in fixed communities. However, the Mongol invasion left Korea in disarray and anomie, and these groups began to become nomadic. Other subgroups of the baekjeong are the chaein and the hwachae. During the Joseon dynasty, they were specific professions like basket weaving and performing executions. They were also considered in moral violation of Buddhist principles, which lead Koreans to see work involving meat as polluting and sinful, even if they saw the consumption as acceptable.
With the unification of the three kingdoms in the seventh century and the foundation of the Goryeo dynasty in the Middle Ages, Koreans systemised its own native caste system. At the top was the two official classes, the Yangban. Yangban means "two classes." It was composed of scholars (Munban) and warriors (Muban). Within the Yangban class, the Scholars (Munban) enjoyed a significant social advantage over the warrior (Muban) class, until the Muban Rebellion in 1170. Muban ruled Korea under successive Warrior Leaders until the Mongol Conquest in 1253. Sambyeolcho, the private Army of the ruling Choe dynasty, carried on the struggle against the Mongols until 1273, when they were finally wiped out to the last man in Chejudo. With the destruction of the warrior class, the Munban gained ascendancy. In 1392, with the foundation of Joseon dynasty, the full ascendancy of munban over muban was final. With the establishment of Confucianism as the state philosophy of Joseon, the Muban would never again gain its former social standing in Korean society.
Beneath the Yangban class were the Jung-in. They were the technicians. They served in lower level government bureaucracy. They were literate, yet were unable to rise into full bureaucratic positions despite passing the gwageo (central government entrance) exam. This class was small and specialised.
Beneath the Jung-in were the Sangmin also called Ssangnom in the vernacular. These were the servant class.
Beneath the Sangmin were the Chunmin. They were the landless peasants. These people composed the majority of Korean society until the 1600s. They were illiterate, and forbidden from marrying into the Yangban class. During the Japanese invasion of 1592, as many government genealogical record was burnt, many of them fabricated their social origin and moved into the Yangban class. With the Manchu invasion of Korea in the 1627 and 1637 and numerous peasant rebellions that followed, the ranks of Yangban families swelled up to more than 60% of the whole country by the late 1800s.
Underneath them all were the Baekjeong. The meaning today is that of butcher. They originate from the Khitan invasion of Korea in the 1000s. As they were defeated, instead of sending them back to Manchuria, The Goryeo government retained them as warriors, spread out throughout Korea. As they were nomads skilled in hunting and tanning of leather, their skill was initially valued by Koreans. Over the centuries, their foreign origins were forgotten, and were only remembered as butchers and tanners.
Korea had a very large slave population, nobi, ranging from a third to half of the entire population for most of the millennium between the Silla period and the Joseon Dynasty. Slavery was legally abolished in Korea in 1894 but remained extant in reality until 1930.
The opening of Korea to foreign Christian missionary activity in the late 19th century saw some improvement in the status of the baekjeong; However, everyone was not equal under the Christian congregation, and protests erupted when missionaries attempted to integrate them into worship services, with non-baekjeong finding such an attempt insensitive to traditional notions of hierarchical advantage. Also around the same time, the baekjeong began to resist the open social discrimination that existed against them. They focused on social and economic injustices affecting the baekjeong, hoping to create an egalitarian Korean society. Their efforts included attacking social discrimination by the upper class, authorities, and "commoners" and the use of degrading language against children in public schools.
With the Gabo reform of 1896, the caste system of Korea was officially abolished. However, the Yangban families carried on traditional education and formal mannerisms into the 20th century. With the democratization of 1990s in South Korea, remnant of such mannerisms and classism is now heavily frowned upon in the South Korean society, replaced by a belief in egalitarianism. However in North Korea, there is still a caste system.
Ancient Hawaiʻi was a caste society. People were born into specific social classes; social mobility was not unknown, but it was extremely rare. The main classes were:
The Spanish and Portuguese colonists of the Americas instituted a relatively loose system of racial and social stratification and segregation based on a person's heritage. The system remained in place in most areas of Spanish America up to the time independence was achieved from Spain. Castes were used to identify classes of people with specific racial or ethnic heritage. However, privileges or restrictions were more related to race and wealth than to a clearly defined system of castes.
Countries in Africa who have societies with caste systems within their borders include Algeria, Burkina Faso, Cameroon, Chad, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, and Somalia.
In West Africa, the osu caste systems of eastern Nigeria and southern Cameroon are derived from indigenous religious beliefs and discriminate against the "Osus" people as "owned by deities" and outcasts.
Similarly, the Mandé societies in Gambia, Ghana, Guinea, Ivory Coast, Liberia, Senegal, and Sierra Leone have caste systems that divide society by occupation and ethnic ties. The Mande caste system regards the jonow slave castes as inferior. Similarly, the Wolof caste system in Senegal is divided into three main groups, the geer (freeborn/nobles), jaam (slaves and slave descendants) and the outcast neeno (people of caste). In various parts of West Africa, Fulani societies also have caste divisions.
Sahrawi-Moorish society in Northwest Africa was traditionally (and still is, to some extent) stratified into several tribal castes, with the Hassane warrior tribes ruling and extracting tribute - horma - from the subservient Znaga tribes. Although lines were blurred by intermarriage and tribal re-affiliation, the Hassane were considered descendants of the Arab Maqil tribe Beni Hassan, and held power over Sanhadja Berber-descended zawiya (religious) and znaga (servant) tribes. The so-called Haratin lower class, largely sedentary oasis-dwelling black people, have been considered natural slaves in Sahrawi-Moorish society.
Mainstream Arab society can be conceived of comprising of three castes, Bedouin (nomads), farmers fellahin (villagers), and hadar (townspeople), though these are often little more than descriptive. Tribe is regarded as more important in Arabian society.
In Yemen there exists a further caste, the Al-Akhdam who are kept as perennial manual workers through practices that mirror untouchability. A traditional saying in the region goes: "Clean your plate if it is touched by a dog, but break it if it's touched by a Khadem." Though conditions have improved somewhat over the past few years, the Khadem are still stereotyped by mainstream Yemenese society, considering them lowly, dirty, ill-mannered and immoral.