'anapsid' originates from Greek, specifically the prefix 'an-' meaning 'without' and 'hapsis' meaning 'arch' or 'loop', referring to the lack of temporal arches in the skull.

'anapsid' was formed in modern scientific English from Greek roots to describe reptiles with skulls lacking temporal openings, and has been used in paleontology since the late 19th century.

Initially, it meant 'without an arch', but over time it evolved into its current meaning of 'a reptile with a skull lacking temporal openings'.