| Noun | 1. | class Thaliacea - small class of free-swimming tunicates; sometimes classified as an order subphylum Tunicata, subphylum Urochorda, subphylum Urochordata, Tunicata, Urochorda, Urochordata - tunicates family Salpidae, Salpidae - a small family of tunicates in the class Thaliacea Doliolidae, family Doliolidae - oceanic tunicates class - (biology) a taxonomic group containing one or more orders |