'amyelencephalous' originates from Greek, specifically the word 'amyelencephalos,' where 'a-' meant 'without,' 'myelos' meant 'marrow or spinal cord,' and 'enkephalos' meant 'brain.'

'amyelencephalos' transformed into the modern English word 'amyelencephalous.'

Initially, it meant 'without brain and spinal cord,' and this meaning has largely remained the same in modern usage.