'appendiceal' originates from Modern/Neo-Latin, specifically the word 'appendiceus', where 'appendix' (from Latin 'appendix') meant 'something attached' and ultimately comes from Latin 'appendere' (from ad- 'to' + pendere 'to hang').

'appendiceal' changed from Medieval/Neo-Latin word 'appendiceus' (Late Latin formation from 'appendix') and was later formed in English by adding the adjectival suffix '-al' to refer to the anatomical appendix, producing the modern English adjective 'appendiceal'.

Initially it was related to the idea of 'something attached' (an appendage), but over time it evolved into the specific anatomical sense 'relating to the appendix' (the vermiform appendix).