Katyayana stated that shabda "speech" is eternal (nitya), as is artha "meaning", and their mutual relation. According to Patanjali, sphoṭa ("meaning") is not identical with shabda, but rather its permanent aspect, while dhvani "sound, acoustics" is its ephemereal aspect.
Om, or Aum, a sacred syllable of Hinduism, Buddhism, and Jainism is considered to be the first resonating vibrational sound within an individual being. It also denotes the non-dualistic universe as a whole. In Buddhism, Om corresponds to the crown chakra and white light.
Bhartrihari on the other hand held a shabda-advaita position, identifying shabda as indivisible, unifying cognition and linguistic performance, ultimately identical with Brahman. Bhartrhari recognizes two entities, both of which may be called shabda, one is the underlying cause of the articulated sounds, while the other is used to express the meaning. Bhartrhari thus rejects the difference posited by logicians between the ontological and the linguistic. His concept of shabda-brahman identifying linguistic performance and creation itself has parallels in the Greek concept of logos.
Language philosophy in Medieval India was dominated by the dispute of the "naturalists" of the Mimamsa school, notably defended by Kumarila, who held that shabda designates the actual phonetic utterance, and the Sphota school, defended by Mandana Mishra, who identified spotha and shabda as a mystical "indivisible word-whole".
In Sikhism the term Shabad has two primary meanings. The first context of the term is to refer to a hymn or paragraph or sections of the Holy Text that appears in Guru Granth Sahib. The main holy scripture of the Sikhs is Sri Guru Granth Sahib (SGGS.) Guru Granth Sahib Ji is organised by chapters of Ragas, with each chapter containing many shabads of that Raga. The first Shabad in Guru Granth Sahib is the Mool Mantar. The script used for the Shabad is Gurmukhi. Shabad is the term also used to refer to hymns within other Sikh scriptures, such as the Dasam Granth of Guru Gobind Singh Ji. The second use of the term Shabad within Sikhism is for the holy name of God, Waheguru.
Esoterically, Shabd is the “Sound Current vibrating in all creation. It can be heard by the inner ears.”  Variously referred to as the Audible Life Stream, Inner Sound, Sound Current or Word in English, the Shabd is the esoteric essence of God which is available to all human beings, according to the Shabd path teachings of Eckankar, the Quan Yin Method, Sant Mat and Surat Shabd Yoga.
Adherents believe that a Satguru, or Eck Master, who is a human being, has merged with the Shabd in such a manner that he or she is a living manifestation of it at its highest level (the “Word made flesh”). However, not only can the Satguru attain this, but all human beings are inherently privileged in this way. Indeed, in Sant Mat the raison d’être for the human form is to meditate on the Sound Current, and in so doing merge with it until one’s own divinity is ultimately realized.
Referring to the Shabd, Sant Kirpal Singh, a contemporary Sant Mat guru, stated that "Naam" ("Word") has been described in many traditions through the use of several different terms. In his teachings , the following expressions are interpreted as being identical to "Naam":
Sant Baljit Singh, a contemporary Sant Mat Master, uses the term "Light and Sound Current." He describes it as the connecting link between human beings and God.