Merriam-Webster Collegiate Dictionary - tunicate

 I. adjective  also ~d  Etymology: Latin tunicatus, from tunica  Date: circa 1623  1.  a. having or covered with a tunic or tunica  b. having, arranged in, or made up of concentric layers a ~ flower bulb  2. of or relating to the ~s  II. noun  Etymology: New Latin Tunicata, from neuter plural of Latin tunicatus  Date: 1889 any of a subphylum (Urochordata syn. Tunicata) of marine chordate animals (as ascidians) that are filter feeders having a thick secreted covering layer, a greatly reduced nervous system, and only in the larval stage a notochord