Definition of: tunicate

(t′nə·kit, -kāt, ty′-) noun
Any of a subphylum (Tunicata or Urochordata) of small marine chordates characterized by the presence of a notochord and tail in the larval stage only and by the secretion of a tough envelope, or tunic, enclosing the body of the adult, as ascidians and salps.
—adjective
1. Pertaining to or resembling a tunicate.
2. Covered with a tunic or tunica.
3. Bot. Having concentric coats, as an onion. [<NL tunicata <L tunicata (animalia) coated (animals), neut. plural of tunicatus, pp. of tunicare clothe with a tunic <tunica a tunic]