Homa (also known as homam or havan) is a Sanskrit word which refers to any ritual in which making offerings into a consecrated fire is the primary action. Its practice by "Rishis" in ancient time refers close to the Vedic era. At present, the words homa/homam and havan are interchangeable with the word Yajna & Agnihotra.
Homas are an important religious practice in Hinduism where they are part of most Sanskar ceremonies. They are also prevalent in current-day Buddhism (particularly the Tibetan and Japanese Vajrayana traditions) and Jainism.