'anion' originates from Greek, specifically the word 'ἄνιον' (anion), where 'ana-/an-' meant 'up' and the root related to 'to go' (ἰέναι/ion) meant 'going'.

'anion' was adopted into 19th-century chemical vocabulary (in New Latin and early modern chemistry) from Greek ἄνιον; chemists used it to name ions that move toward the anode, and it entered modern English as 'anion'.

Initially it literally meant 'that which goes up' or 'going to the anode'; over time it has come to mean more specifically a 'negatively charged ion' in chemistry.