'aphetism' originates from Greek, specifically the word 'aphesis', where 'a-' meant 'away' (or 'off') and 'phesis' meant 'a letting go or release'.

'aphetism' changed from the Classical/Greek term 'aphesis' into Late Latin/medieval scholarly usage (as 'aphesis') and was later adopted into English linguistic terminology as 'aphetism' in modern descriptions of sound loss.

Initially, it meant 'a letting go' or 'release' in a general sense, but in linguistic usage it evolved to mean specifically the omission or loss of an initial sound or syllable in a word.