'aphetic' originates from Greek, specifically the word 'aphesis', where 'aphesis' meant 'a letting go' or 'release' (hence 'omission').

'aphetic' entered scientific/linguistic use via New Latin/Modern scholarly formation from Greek 'aphesis' and appeared in English usage in formations describing phonological loss; the English adjective 'aphetic' developed from these scholarly uses.

Initially it referred more generally to 'letting go' or 'release' (from Greek), but in linguistic contexts it came to mean specifically 'relating to the omission of an initial vowel' and now denotes that phonological phenomenon.