'oxyanion' originates from the combining form 'oxy-' (from Greek 'oxys') and 'anion' (from Greek 'anion'), where 'oxy-' came to be used in chemistry to indicate oxygen and 'anion' referred to a negatively charged ion.

'oxyanion' was formed in modern chemical nomenclature by combining the prefix 'oxy-' (used since the 19th century to denote oxygen-containing groups) with 'anion' (a term adopted into English from Greek via New Latin/French in the 19th century), producing the compound term used in inorganic chemistry.

Initially, 'anion' historically meant 'that which goes up' (referring to movement toward the anode in early electrochemistry), and 'oxy-' originally meant 'sharp' or 'acid' in Greek; over time the combined form 'oxyanion' evolved to mean specifically 'an anion that contains oxygen'.