'mummify' originates from the Medieval Latin word 'mummificare', itself formed from 'mummy' + Latin suffix '-ficare' (to make), where 'mummy' referred to a preserved corpse.

'mummify' developed into English via Late Latin/Old French influences; the noun 'mummy' came into Medieval Latin from Arabic 'mūmiyā' (from Persian 'mūm' meaning 'wax' or 'bitumen'), and the verb was formed in English by adding the productive suffix '-fy' to 'mummy'.

Initially it meant 'to turn into or treat as a mummy (often using bitumen/wax-based substances)'; over time it broadened to mean 'preserve by drying/embalming' and acquired figurative senses of making something rigid or unchanging.