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

'anaptychi' was adopted into scientific Latin from Greek, and eventually became the modern English term 'anaptychi' used in paleontology.

Initially, it referred to something unfolded or opened, but over time it evolved into its current meaning of a specific fossilized jaw plate.