'apostolos' originates from Ancient Greek, specifically the word 'ἀπόστολος', where 'ἀπό-' meant 'away/from' and the root related to 'στέλλειν' meant 'to send'.

'apostolos' changed from the Ancient/Koine Greek word 'ἀπόστολος' into Late Latin 'apostolus', which influenced Old French and Middle English forms (e.g. 'apostel') and contributed to the English word 'apostle'; the transliteration 'apostolos' preserves the original Greek form.

Initially, it meant 'one sent away' or 'a messenger', but over time it became specialized to mean 'an apostle' (especially one of the early followers of Jesus) and is also used as a personal name.