Vedic sacrifices called yajñas or yāgas are an ancient religious institution. They have exercised a tremendous influence on the Hindu society over the millennia.
They are generally classified into three groups: pākayajñas, haviryajñas and somayāgas.
Though the word ‘havis’ means any oblatory material, it generally refers to uncooked materials like barley, rice, milk or ghee.
Seven haviryajñas are mentioned in the śrautasūtra literature. They are: Agnyādheya, Agnihotra, Darśapūrṇamāsa, Cāturmāsya, Āgrayaṇa, Nirūḍhapaśu-bandha and Sautrāmaṇī.
All these are performed in the three Vedic fires viz., gārhapatya, dakṣiṇā and āhavanīya.