'apheresis' originates from Ancient Greek, specifically the word 'aphairesis', where 'aphaires-' (from 'aphairein') meant 'a taking away' or 'removal' and the suffix '-esis' marked an action or process.

'aphairesis' passed into Late Latin/medieval Latin as 'aphaeresis' and was adopted into English as 'apheresis', with spelling and pronunciation adjusted over time.

Initially it meant 'a taking away' in a general sense; over time it developed specialized senses in English, notably a medical sense referring to removal of blood components and a linguistic sense referring to loss of an initial sound.