What is Yoga?
In Vedic Sanskrit, the more commonly used, literal meaning of the Sanskrit word yoga which is "to add", "to join", "to unite", or "to attach" from the root yuj, already had a much more figurative sense, where the yoking or harnessing of oxen or horses takes on broader meanings such as "employment, use, application, performance" (compare the figurative uses of "to harness" as in "to put something to some use"). All further developments of the sense of this word are post-Vedic. More prosaic moods such as "exertion", "endeavour", "zeal" and "diligence" are also found in Epic Sanskrit.
There are very many compound words containing yog in Sanskrit. Yoga can take on meanings such as "connection", "contact", "method", "application", "addition" and "performance". For example, guṇá-yoga means "contact with a cord"; chakrá-yoga has a medical sense of "applying a splint or similar instrument by means of pulleys (in case of dislocation of the thigh)"; chandrá-yoga has the astronomical sense of "conjunction of the moon with a constellation"; puṃ-yoga is a grammatical term expressing "connection or relation with a man", etc. Thus, bhakti-yoga means "devoted attachment" in the monotheistic Bhakti movement. The term kriyā-yoga has a grammatical sense, meaning "connection with a verb". But the same compound is also given a technical meaning in the Yoga Sutras (2.1), designating the "practical" aspects of the philosophy, i.e. the "union with the Supreme" due to performance of duties in everyday life
In Hindu philosophy, the word yoga is used to refer to one of the six orthodox (āstika) schools of Hindu philosophy.[note 1] The Yoga Sutras of Patanjali are often labelled as Rāja yoga. According to Pāṇini, a 6th-century BCE Sanskrit grammarian, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau (to concentrate). In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology. In accordance with Pāṇini, Vyasa (c. 4th or 5th century CE), who wrote the first commentary on the Yoga Sutras, states that yoga means samādhi (concentration). In other texts and contexts, such as the Bhagavad Gītā and the Hatha Yoga Pradipika, the word yoga has been used in conformity with yujir yoge (to yoke).