'erythroplakia' originates from Greek, specifically the words 'erythros' and 'plax' (or 'plakos'), where 'erythros' meant 'red' and 'plax/plakos' meant 'plate' or 'patch'.

'erythroplakia' was formed in New Latin/medical Neo-Latin from the Greek elements 'erythros' + 'plax(plakos)' and was adopted into Modern English medical terminology without major phonetic change.

Initially it meant 'red patch' in the Greek-derived compound sense, but over time it has come to denote specifically 'a red patch on a mucous membrane that is often regarded as a potentially precancerous lesion'.