'ascidioidea' originates from New Latin, specifically built from 'Ascidi-' (from Latin 'Ascidia' < Greek 'askidion') plus the Greek-derived suffix '-oidea' meaning 'resembling' or used to form superfamily names, where 'askidion' meant 'little bag'.

'ascidioidea' was formed in New Latin scientific nomenclature from the name for ascidians ('Ascidia' which comes from Greek 'askidion') combined with the suffix '-oidea'; it entered modern scientific English usage as the name of a superfamily of ascidians.

Initially the root referred to the small bag-like shape ('little bag'), and over time the combined form came to denote the taxonomic group (the superfamily of organisms resembling ascidians) rather than a literal 'little bag'.