Chetana is derived from the root ‘chit’ to be conscious of (Chetati). Although Chetana is used in the masculine form, cetana, the feminine form is more commonly used in philosophy in Hinduism in the sense of consciousness.
The word Chetana however, is not found in Vedic literature. Sri Krishna declares in the Bhagavad Gita that he is the chetana in the living being (Gita 10 – 22). Commenting on Chetana, Adi Shankaracharya says that Chetana means the intellectual activity which manifests when the body and senses combine.
The Samkhya School postulates that Chetana (in buddhi or the intellect) is a consequence of the presence of purusha in achetana (the unintelligent).
Vedanta equates cetana with Brahman occasionally and holds the theory that chetana (Brahman) is the cause of the world (cetanakaranavadinah) (Adi Shankara on Brahmasutra 1-6-12).
In classical Sanskrit literature, cetana means sentient beings. For example, Kalidasa uses the term cetanacetanesu in his Meghadutam in the sense, among sentient and insentient beings.