'ascidiacea' originates from New Latin, specifically the word 'Ascidiacea', where the root 'ascid-' ultimately comes from Greek 'askidion' meaning 'little bag' (diminutive of 'askos' meaning 'bag').

'Ascidiacea' changed from Latin 'ascidia' (from Greek 'askidion') and was used in New Latin taxonomy as 'Ascidiacea', eventually becoming the modern scientific name 'ascidiacea' in English usage.

Initially it referred to the 'little bag' (the sac-like body form), but over time it evolved into the current meaning denoting the taxonomic group (the class of sea squirts).