'apostleship' originates from Greek via Latin and Old English: ultimately from Greek 'apóstolos' (ἀπόστολος), meaning 'one sent away' or 'messenger', with the English suffix '-ship' added to indicate office or condition.

'apóstolos' (Greek) became Latin 'apostolus', then Old English 'apostol'/'æpostol', later Middle English 'apostle', and finally the compound form 'apostleship' was formed in English by adding the suffix '-ship' to denote the state or office of an apostle.

Initially it referred to 'one who is sent' (an apostle). Over time, with the suffix '-ship' it came to mean 'the office, authority, or mission associated with an apostle,' which is the modern sense.