'Agnatha' originates from New Latin (taxonomic usage), ultimately from Greek 'agnathos', where the prefix 'a-' meant 'without' and 'gnathos' meant 'jaw'.

'Agnatha' was formed from the Greek word 'agnathos' and adopted into scientific Latin/Modern English taxonomic usage as 'Agnatha' to name the jawless vertebrate group.

Initially it literally meant 'without jaws'; over time it became the formal name for the group of jawless vertebrates and retains the core meaning of 'jawless'.