'cyclostome' originates from Greek, specifically the words 'kyklos' and 'stoma', where 'kyklos' meant 'circle' and 'stoma' meant 'mouth'.

'cyclostome' changed from New Latin 'Cyclostoma' (used in scientific taxonomy) and eventually became the modern English word 'cyclostome'.

Initially, it meant 'circle-mouth' (referring to a circular mouth), but over time it evolved into its current meaning referring to jawless fishes of the group Cyclostomata.