'aplasia' originates from Greek, specifically the word 'aplasía', where 'a-' meant 'not' and 'plasis' meant 'formation' or 'molding'.

'aplasia' came into New Latin/medical Latin from Greek 'aplasía' and was adopted into English in medical usage to denote lack of development.

Initially, it literally meant 'not-formation' (lack of formation); over time it became the technical medical term for the failure of an organ or tissue to develop.