'arsenite' originates from New Latin/Modern scientific formation combining 'arsenic' and the mineral-forming suffix '-ite', where 'arsenic' ultimately traces back to Greek 'arsenikon' (ἀρσενικόν).

'arsenite' changed from Medieval/Modern Latin forms related to 'arsenic' and the suffix '-ite' (used for minerals and salts) and entered English scientific usage as 'arsenite'.

Initially the element-name base referred to arsenic-related minerals and compounds; over time the formed word 'arsenite' came to mean specifically the salts or anions of arsenous (arsenic(III)) acid.