Agni is fire, and the very first hymn of the Rigveda is addressed to him, a placement that reflects his function rather than a ranking of importance. In the logic of Vedic sacrifice Agni is not merely one god among those worshipped but the mechanism of worship itself: he is the mouth of the gods, and an offering placed in the fire is carried up by him as smoke to whichever deity it is meant for. He is thus the priest among the gods and the indispensable intermediary between earth and heaven, present wherever fire is, in the domestic hearth, on the altar, in lightning, in the sun, and in the fire of digestion within the body.
Agni's name shares its Indo-European root with the Latin ignis, source of the English ignite and igneous, a linguistic link that places him, alongside deities such as Dyaus and Ushas, among the clearest cases of a Vedic god's name surviving, transformed, in the vocabulary of distant European languages descended from the same ancestral tongue. Later Puranic iconography gives Agni a fixed visual form distinct from his Vedic abstraction: red-skinned, sometimes shown with two faces or several flaming tongues, riding a ram, and carrying a ladle for pouring oblations, an axe and a flaming torch, images that translate the purely functional Vedic fire-god into the fully pictured, temple-worshippable deity later Hindu art required.