'anthesteriac' originates from Ancient Greek, specifically the word 'Anthesteria', where 'anthos' meant 'flower' (from ἄνθος) and the adjectival element '-iakos' (rendered in English as '-iac') signified 'pertaining to'.

'anthesteriac' was formed in English as a learned adjective borrowed from the Greek noun 'Anthesteria' via scholarly and Latin usages; the Greek festival name was adapted into English and combined with a Greek-derived adjectival ending to produce 'anthesteriac'.

Initially it referred specifically to the festival 'Anthesteria' itself or things directly pertaining to it; over time it has been used more broadly for anything connected with that festival, its rites, or its iconography.