'attacheship' originates from French, specifically from 'attaché' (past participle of 'attacher', meaning 'to attach') combined with the English suffix '-ship' (denoting office or condition).

'attaché' was borrowed into English from French; English then formed 'attacheship' by adding the native suffix '-ship' (from Old English 'scipe' meaning 'state, condition, office'), creating a noun meaning the office or condition related to an attaché.

Initially it referred specifically to the office or rank of an attaché; in some rare or archaic uses it also came to be used more generally for a state of attachment. The primary modern sense remains the office/post meaning.