An intern is someone who works in a temporary position with an emphasis on on-the-job training rather than merely employment (SIH-199), making it similar to an apprenticeship. Interns are usually college or university students, but they can also be high school students or post graduate adults seeking skills for a new career. Student internships provide opportunities for students to gain experience in their field, determine if they have an interest in a particular career, create a network of contacts, or gain school credit. Internships provide employers with cheap or free labor for (typically) low-level tasks, and also the prospect of interns returning to the company after completing their education and requiring little or no training.
An internship may be either paid, unpaid or partially paid (in the form of a stipend). Paid internships are most common in the medical, architecture science, engineering, law, business (especially accounting and finance), technology and advertising fields. Internships in non-profit organization such as charities and think tanks are often unpaid, volunteer positions. Internships may be part-time or full-time; typically they are part-time during the university year and full-time in the summer, and they typically last 6–12 weeks, but can be shorter or longer. The act of job shadowing may also constitute as interning.
Internship positions are available from businesses, government departments, non-profit groups and organizations. Due to strict labor laws, European internships are mostly unpaid, although they are still popular among non-Europeans in order to gain international exposure on one's résumé and for foreign language improvement.
Internships exist in various industries and settings. Here are two primary types of internships that exist in the United States.
Some companies will find and place students in internships for a fee; such internships are mostly unpaid. In some cases companies charge to assist with a search, promising to refund their fees if no internship is found. What is included in such paid programs varies by company. Overall, the advantages are that they provide internship placements at reputable companies, provide controlled housing in a new city, mentorship and support throughout the summer, networking, weekend activities in some programs, and sometimes academic credit.
Another form of paying for internships is through charity auctions, where a company with an internship will select a charity to get the proceeds of the auction. In some cases, companies have created internships simply to help charities.
Fee-based programs, and charity auctions, restrict internship opportunities to students in wealthier families who can afford paying thousands of dollars while the student works for little or no wages, in exchange for improving professional work opportunities after graduation. But the head of one company specializing in such internships said that "The average student comes from the middle class, and their parents dig deep" to pay for it. He said that his company had begun, in 2008, to fund scholarships and grants for low-income applicants.
Many internships in the United States are career specific. Students often choose internships based on their major at the university/college level. It is not uncommon for former interns to acquire full-time employment at an organization once they have enough necessary experience. The challenging job market has made it essential for college students to gain real world experience prior to graduation. Jeff Gunhus, CEO for one of the largest internship programs in the U.S. said, "Undergraduates face different challenges than the average person looking for a career."  In the US, company internships are at the center of NIGMS funded biotechnology training programs for science PhD students. One example is the Biotechnology Training Program - University of Virginia.
Many students do internships in a different country to get international experience and learn an extra language. The meaning of an internship can be different around the globe. Organizations such as AIESEC exist to coordinate these internships for students.
Ireland is fast becoming a highly sought after destination for internships. Participants come from all over the world to experience some of the best resources available in Europe. Students of all ages can experience all aspects of the culture Ireland has to offer while completing their internships. A combination of accommodation is available, from host families to hostels to sharing in apartments with other nationalities. Students come to Ireland anytime from 4 weeks up to a year. Student preferences are adhered to - usually getting their first choice in their chosen field, media, hotel reception, cooking, marketing, business etc. To get a full support system while they are here it is highly recommended that students make a reservation through a reliable company that specializes in placing participants in a host company that best matches their needs. In this way if there is a problem with the host company or the accommodation they can get help in acquiring another company or alternative accommodation straight away without delay. Most internships in Ireland are unpaid but the host company may provide a full travel card for the duration of the internship. Chefs normally get free accommodation if working for a hotel. A reasonable comprehension of English is essential when seeking internships in Ireland, some agencies will organize an intensive English language course from one to three weeks depending on the length of stay before the intern joins a host company.
At Spanish universities it is uncommon to do an internship during the education period. The real working experience for students starts when they are done with their study. However, Spanish companies are getting more used to having students doing an internship at their company nowadays. Mostly these are international students from other European countries. Spain is a popular country for students to go to for a short period of time to do an internship. Often, students want to learn Spanish, and this is a perfect opportunity for them to do so. Another reason to go to Spain for an internship could be the opportunity to increase their cultural awareness or to experience working in an international setting. Students found that it is hard to get in contact with most Spanish businesses. The best way to find a good company to work at will be with the help of a placement organization. The normal stage compensation rate in Spain is around €500.
South Africa and Cape Town in particular are becoming more popular among international students for internships, student exchange and volunteer work. Cape Town is also popular for medical students who want to do a summer internship at for instance Groote Schuur hospital. Gaining work experience in this different environment with more pressure and different challenges is very valuable for future employees. Most internship’s in South Africa are unpaid at present but some companies are willing to cover some of the living costs. However, a great deal of companies are not familiar to interns and do not fully know the educational or academic value it provides its students. When this is not explained to the company, it could happen that the intern is merely seen as a cheap labourer rather than a valuable asset to the company. It is therefore practice by many students to pay an internship company that sorts out the agreements with the companies and arranges accommodation during their stay in for example Cape Town. However, there are also new initiatives that provide students with all the necessary information and tools to sort out their own internship  in South Africa.
Since the Italian University System entered into the Bologna process, an internship experience (commonly referred to by the French term stage) has been made compulsory for almost all those studying for a bachelor's or a master's degree (especially in technical, economic or scientific faculties). Its goal should be reducing the gap between the companies' demands and the too theoretical learning offered by Italian universities. However, since the internship is usually made at university as well and since the few companies that accept student interns don't offer a proper training, it is not a real work experience. Almost all the students therefore have to do a second or a third internship after they are done with their studies, this time in a company, hoping to receive a proper professional training, being hired afterwards in the same company, or in another company in a close or related business. The internship period can last up to 6 months, renewable for other 6 months, so the total period can be up to 12 months. Internships in Italy can be both paid and not paid: students internships, especially the ones not involved with the development of a thesis, are usually not paid; almost all the graduate internships, instead, are paid, but the remuneration is extremely low, around 600 euros gross per month, about 1/4 of the gross monthly remuneration of an hired young graduate employee, and without benefits other than the lunch (so no housing, no 13th/14th mensilities, no paid holidays, no parental leave). This poses a huge problem for fresh graduates, considering as well that some companies use graduate interns just to save money, making them work for 6 to 12 months without giving them a decent remuneration, without offering them a proper training/formation, and without hiring them after the internship even if they showed to be productive,fast-learner and trustworthy workers. In other words, a relevant percentage of the Italian graduates, after one or even two years from the end of their studies (in some cases even master's studies), are still searching for a real job, that can offer stability and a decent remuneration. This, together with the long time necessary to graduate in Italy (Italian universities are very difficult), is part of the reason why graduate Italians leave the family home very late, usually in their early 30s.
Internships are often referred to as 'sandwich placements' in the UK and are validated work experienced opportunity as part of a degree program. University staff give students access to vacancies and students apply direct to employers. Some universities hold fairs and exhibitions to encourage students to consider the option and to enable students to meet potential employers.(AGR report 2008) In the modern labour market graduates with work experience in the form of sandwich placements are not only deemed more desirable to employers but also research has demonstrated they attain higher level degree classifications than those graduates without such experience.
The purpose of these internships/placements is varied. Some University students see it as a way to develop their employability by utilising the academic elements of their degreee in a practical setting. International students may also seek to get understanding about how work is conducted in the English-speaking world and to experience cultural diversity.
The UK based website, Interns Anonymous has been highlighting the plight of unpaid interns and problems in the graduate job market since March 2009. .
In Germany there are different kinds of internships as well. As in most other countries, most students take their internship during the fourth or fifth semester of their degree. In some fields of study it is common to write the final thesis in a company. Another type of internship has emerged, the post graduation internship. The high unemployment in Germany during the last years has made it hard for people to find the right job, especially for people that have just graduated and lack work experience. Because of this, many offer to do an internship at their preferred place of employment while earning very little, in the hope of landing a job there in the future.
At the French universities it is also most common to do an internship, in France called stage, during the third or fourth year of your studies. The duration of the internships varies from 2 to 6 months, but very seldom longer than that. In France it is also becoming more popular to do an internship after one has finished studying. Mostly for students that did not get the chance to do an internship during their study career, and try to gain some working experience this way. Most times with the thought of getting hired after the internship period. An internship in France is also popular for international students. The number one reason to do an internship in France is to learn the language. A lot of French companies seem to be open to students from different countries. It is a big plus for companies to have employees who speak multiple languages.
In the Netherlands it is also common to do an internship during college. Just like in France it is called stage. Students will go intern for approximately 5 months. Companies are not obligated to pay the student, so sometimes small companies won't pay anything. The normal internship compensation rate in the Netherlands is around €300 .
It is not seen as appropriate to work without pay unless it is done as part of a work-trial where a person is tested by the authorities as part of plan to get the individual back into the workspace  The company is then compensated and the intern gets welfare during this period, which normally lasts about three months. The Trade Unions monitor this area very thoroughly so an intern cannot result in the loss of a paid job 
India has become an important destination for international internship from several western developed countries since early 2000.Some organisations also organize an intensive Indian language, culture, ayurveda and yoga courses from few weeks to several months depending on the length of stay before the intern joins associate host organisations.
Unlike in most other countries, very few students pursue internships during their college in India. This is primarily because, the university education system in India is focused more on marks than on students gaining practical exposure. As a result, even companies in India do not use internships as a recruitment model, in contrast with more developed countries where internships are extensively used as a tool to recruit talent.
This trend seems to be changing in the recent years, as initiatives like www.twenty19.com  are educating Indian students on the advantages and the need for internships during college days. This portal also serves as a simple medium to enable students to easily apply to internships in their areas of interest.
An intern is somebody who works in a job for a short time so as to train while working, unlike just working which offers little to no training.