'atar' originates from Avestan, specifically the word 'ātar', where 'ātar' meant 'fire'.

'atar' passed from Avestan 'ātar' into Middle Persian (classical forms like 'ādar' or 'ātar') and entered English usage mainly through scholarly transliteration of Avestan and Persian religious texts.

Initially it meant 'fire' (a physical element) in ancient Iranian languages; over time, especially within Zoroastrian religious use, it came to be associated more specifically with a sacred or ritual fire.