[too-ni-kit, -keyt, tyoo-]
  1. Zoology. any sessile marine chordate of the subphylum Tunicata (Urochordata), having a saclike body enclosed in a thick membrane or tunic and two openings or siphons for the ingress and egress of water.
adjective Also tu·ni·cat·ed.
  1. (especially of the Tunicata) having a tunic or covering.
  2. of or relating to the tunicates.
  3. Botany. having or consisting of a series of concentric layers, as a bulb.

Origin of tunicate

First recorded in 1615–25, tunicate is from the Latin word tunicātus wearing a tunic. See tunic, -ate1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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Historical Examples of tunicate

British Dictionary definitions for tunicate


  1. any minute primitive marine chordate animal of the subphylum Tunicata (or Urochordata, Urochorda). The adults have a saclike unsegmented body enclosed in a cellulose-like outer covering (tunic) and only the larval forms have a notochord: includes the sea squirtsSee also ascidian
adjective Also: tunicated
  1. of, relating to, or belonging to the subphylum Tunicata
  2. (esp of a bulb) having or consisting of concentric layers of tissue

Word Origin for tunicate

C18: from Latin tunicātus clad in a tunic
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for tunicate

1760, from Latin tunicatus, past participle of tunicare "to clothe in a tunic," from tunica (see tunic). As a noun, from 1848.

Online Etymology Dictionary, © 2010 Douglas Harper

tunicate in Science


  1. Any of various primitive marine chordate animals of the subphylum Tunicata, having a rounded or cylindrical body that is enclosed in a tough outer covering. Tunicates start out life as free-swimming, tadpolelike animals with a notochord (a primitive backbone), but many, such as the sea squirts, lose the notochord and most of their nervous system as adults and become fixed to rocks or other objects. Tunicates often form colonies.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.