'anaptychus' originates from Greek, specifically the word 'anaptychos,' where 'ana-' meant 'up' or 'again' and 'ptychos' meant 'fold.'

'anaptychos' was adopted into scientific Latin as 'anaptychus,' and eventually became the modern English word 'anaptychus.'

Initially, it referred to something that could be unfolded, but in paleontology, it came to mean the specific jaw plate structure in ammonites.