• synonyms


[uh-sid-ee-uh n]Zoology
  1. any solitary or colonial tunicate of the class Ascidiacea, exhibiting in the larval stage the vertebrate characteristics of a notocord and hollow nerve cord.
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  1. belonging or pertaining to the class Ascidiacea.
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Origin of ascidian

1855–60; < New Latin Ascidi(um) a tunicate genus (see ascidium) + -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ascidian

Historical Examples of ascidian

  • So that in this respect the ascidian larva is nearer to the original type than the tadpole or any other existing animal.

    The Evolutionist at Large

    Grant Allen

  • The ascidian has only one eye inside its useless brain, while the tadpole and all other vertebrates have two from the very first.

  • The ascidian when born is a tiny, free-swimming, tadpole-like creature with a slender finned tail.

  • Chabry had published in 1887 some interesting results on the Ascidian egg, which strongly supported the Roux-Weismann theory.

    Form and Function

    E. S. (Edward Stuart) Russell

  • The beginning of man an ascidian—his ultimate development as an angel, a pear-shaped, transparent bag.

British Dictionary definitions for ascidian


  1. any minute marine invertebrate animal of the class Ascidiacea, such as the sea squirt, the adults of which are degenerate and sedentary: subphylum Tunicata (tunicates)
  2. ascidian tadpole the free-swimming larva of an ascidian, having a tadpole-like tail containing the notochord and nerve cord
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  1. of, relating to, or belonging to the Ascidiacea
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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