Yoga, Sanskrit for "yoking" or "union", is a group of physical, mental, and spiritual practices or disciplines that originated in ancient India, aimed at controlling and stilling the mind, and recognizing the detached 'witness-consciousness' as untouched by the activities of the mind and mundane suffering. There are a broad variety of yoga schools, practices, and goals in Hinduism, Buddhism, and Jainism, and traditional forms and modern methods of yoga are practiced worldwide.
There are broadly two kinds of theories on the origins of yoga. The linear model argues that yoga has Aryan origins, as reflected in the Vedic textual corpus, and influenced Buddhism; according to Crangle, this model is mainly supported by Hindu scholars. The synthesis model argues that yoga is a synthesis of indigenous, non-Aryan practices with Aryan elements; this model is favoured in western scholarship.
Yoga is first mentioned in the Rigveda and also referenced in many Upanishads. The first known formal appearance of the word "yoga", with the same meaning as the modern term, is in the Katha Upanishad, probably composed between the fifth and third century BCE.