'apostle' originates from Greek, specifically the word 'apostolos', where 'apo-' meant 'away' and 'stellein' (or related root) meant 'to send'.

'apostle' changed from Late Latin 'apostolus' and Old English 'apostol' and eventually became the modern English word 'apostle'.

Initially, it meant 'one sent out' or 'messenger'; over time it came to refer especially to the twelve primary disciples of Jesus and, by extension, to zealous promoters of a cause.