'oxidant' originates from French, specifically the word 'oxydant', where the prefix 'oxy-' ultimately comes from Greek 'oxys' meaning 'sharp' or 'acid', and the suffix '-ant' is an agent-forming ending.

'oxidant' developed in English in the 19th century from French 'oxydant' and from the verb 'oxidize' (formed from 'oxide' and the -ize suffix). 'Oxide' itself comes from New Latin/Modern French derived from Greek elements related to 'oxys'.

Initially the related terms referred specifically to substances that form oxides by combining with oxygen; over time the meaning broadened to the modern chemical sense of a substance that oxidizes another (often by accepting electrons).