In Hinduism, yajña (IAST: yajña) ("sacrifice") is the ritual act of offering labour or materials. In more formal ceremonies, it is a practice from historical Vedic religion where specific offerings are made, accompanied by the chanting of Vedic mantras. Agni Yajna is the ritual offering of ghee, grain and havana sámagri ("herbal preparations") into a sacred fire.
The meaning of the word yajna is derived from the Sanskrit verb yaj, which has a threefold meaning of worship of deities (devapujana), unity (sangatikarana) and charity (dána). An essential element is the ritual fire – the divine Agni – into which oblations are poured, as everything that is offered into the fire is believed to reach the deity or deities.
The Sanskrit word is related to the Avestan term yasna of Zoroastrianism. Unlike the Vedic yajna, the Yasna is the name of a specific religious service, not a class of rituals, and they have "to do with water rather than fire".
Temple rites in modern-day Hinduism are a combination of both Vedic and agamic rituals. The ritualistic portion of the Hindu scriptures is called karmakanda. Parts of Vedas which describe or discuss the yajñas fall into this portion.