'apostemate' originates from Greek, specifically the word 'apostēma', where 'apo-' meant 'away' and 'stēma' (from histēmi) related to 'a standing' (hence a thing standing apart, a swelling or abscess).

'apostemate' entered English via Latin 'apostema' (and Medieval Latin 'apostema') and Middle English/early modern uses such as 'aposteme' or 'apostema', eventually appearing in English texts as 'apostemate' in medical contexts (now largely archaic).

Initially it referred broadly to a 'thing standing away' (a swelling or protrusion), and over time the meaning narrowed to specifically denote a 'suppurating swelling' or 'abscess'.