'non-elongated' is a compound formed from the negative prefix 'non-' (from Latin 'non', meaning 'not') and 'elongated'. 'Elongated' originates from Latin 'elongatus', the past participle of 'elongare', where 'e-/ex-' meant 'out' and 'longus' meant 'long'.

'elongate' entered English via Late Latin/Old French from Latin 'elongare' and developed into the past participle form 'elongated'; the modern adjective 'non-elongated' is a straightforward negation using the productive English prefix 'non-'.

Originally related to the action 'to make long' (to lengthen), 'elongate' and its participle 'elongated' retained that sense; adding 'non-' produces the direct opposite meaning 'not lengthened' or 'not long'.