'apologia' originates from Greek, specifically the word 'ἀπολογία' (apologia), where the prefix 'ἀπο-' (apo-) meant 'away/from' and 'λογία' (logia) related to 'speaking' or 'account'.

'apologia' passed from Greek into Late Latin and Medieval Latin as 'apologia,' and was adopted into English (as 'apologia'); the plural form 'apologiae' reflects the original Latin/Greek plural ending and has been used in scholarly and rhetorical contexts.

Initially, it meant 'a speech in defense' in classical Greek; over time it came to mean more broadly 'a formal defense or justification' in modern English usage.