Agnihotra — The Twice-Daily Vedic Fire Sacrifice
The agnihotra (fire + oblation) is the most fundamental of Vedic daily rituals: the twice-daily offering of milk or ghee into a sacred fire performed at sunrise and sunset by eligible householders who have formally established and maintain the sacred fires (agnihotrins). It is described extensively in the Taittirīya Saṃhitā and the Śatapatha Brāhmaṇa. The agnihotra fire is maintained continuously from the day of the householder's marriage and never allowed to go out — it is the living symbol of the householder's relationship with the divine order (ṛta).
In the broader Vedic framework, agnihotra is a Śrauta fire rite directed to the deities and ultimately to the yajña-svāmī; it should not be counted as one of the five pañca-mahāyajñas. The Bhagavad Gītā honors the agnihotra among the various types of yajña: yajñāṃ yajño 'smi ('I am the yajña among yajñas'). The Mīmāṃsā school held the agnihotra to be the paradigmatic Vedic ritual from which all other rituals derive. In Śrī Vaiṣṇava understanding, the fire sacrifice is understood as directed ultimately to Bhagavān Nārāyaṇa who is the yajña-svāmī (lord of all sacrifice) — ahaṃ hi sarva-yajñānāṃ bhoktā ca prabhur eva ca (Gītā 9.24: 'I am indeed the enjoyer and lord of all yajñas').
For those Śrī Vaiṣṇava brāhmaṇas who maintain the three sacred fires (treta-agni: gārhapatya, āhavanīya, dakṣiṇa-agni), the agnihotra is a central daily observance along with sandhyāvandanam and brahma-yajña. In contemporary practice, the full agnihotra with three fires is maintained by fewer families, but the principle of deva-yajña is preserved through the daily thiruvarādhanam (home worship) — which the Āchāryas interpret as the Śrī Vaiṣṇava householder's equivalent of the Vedic agnihotra.