'non-carnivorous' originates from Latin combining elements: the prefix 'non-' (from Latin 'non') meaning 'not', and 'carnivorous' from Latin 'carnivorus', where 'carni-' (from 'caro, carnis') meant 'flesh' and '-vorous' (from 'vorare') meant 'to devour'.

'non-carnivorous' was formed in English by adding the negative prefix 'non-' to 'carnivorous'. 'Carnivorous' entered English via Latin 'carnivorus' (through Medieval/Old French and Middle English) and then combined with 'non-' in Modern English usage.

Initially, 'carnivorous' meant 'flesh-devouring' in Latin; 'non-carnivorous' initially meant 'not flesh-devouring' and has retained the general sense of 'not feeding on other animals' in modern usage.