'anthomaniac' originates from Greek, specifically the combining form 'anth-' (from 'ánthos'), where 'ánthos' meant 'flower', combined with the suffix '-maniac' from Greek 'māníā' meaning 'madness' or 'frenzy'.

'anthomaniac' was formed in English by combining the Greek-derived combining form 'anth(o)-' with the element '-maniac' (as in 'bibliomaniac', 'pyromaniac') in modern coinage; it does not descend directly from a single older English word but follows the pattern of 19th–20th century English formations using classical roots.

Initially it was coined to denote 'a person with a mania for flowers' and over time it has retained that meaning, used chiefly as a rare or literary term for obsessive interest in flowers.