'asmodeus' originates from Hebrew and Avestan influences: Hebrew 'Ashmedai' (אֲשְׁמְדַּי) and Avestan 'Aēšma-daēva' (or 'Aeshma-daeva'), where the Avestan element 'aēšma' meant 'wrath' and 'daēva' meant 'demon' or 'false god'.

'asmodeus' passed from the Avestan/Zoroastrian concept 'Aēšma-daēva' into Hebrew as 'Ashmedai', then into Greek as 'Asmodaios' and Latin as 'Asmodeus', and finally entered Medieval Latin and Middle English demonological texts as 'Asmodeus'.

Initially it referred broadly to a 'wrathful demon' in Old Iranian religion, but over time (especially in Jewish and Christian texts) the figure became more specifically associated with lechery, marital misfortune, and particular malign influences; in later literature it is used both as a proper-name demon and a symbol of sexual vice.