Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.


[From New Latin Ascidia, genus name, from Greek askidion, diminutive of askos, wineskin.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Zoology) 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. (Zoology) ascidian tadpole the free-swimming larva of an ascidian, having a tadpole-like tail containing the notochord and nerve cord
(Zoology) of, relating to, or belonging to the Ascidiacea
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(əˈsɪd i ən)

1. any tunicate of the class Ascidiacea, having in the larval stage a notochord, a characteristic of the embryonic vertebrate.
2. belonging or pertaining to the class Ascidiacea.
[1855–60; < New Latin Ascidi(um) a tunicate genus < Greek askídion a small bag + -an1]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.ascidian - minute sedentary marine invertebrate having a saclike body with siphons through which water enters and leavesascidian - minute sedentary marine invertebrate having a saclike body with siphons through which water enters and leaves
tunicate, urochord, urochordate - primitive marine animal having a saclike unsegmented body and a urochord that is conspicuous in the larva
Ascidiaceae, class Ascidiaceae - sometimes classified as an order: sea squirts
sea squirt - ascidian that can contract its body and eject streams of water
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The ascidian fauna of the Chilean coast comprises around 72 species.
Some chordate ascidians undergo whole-body regeneration (Schultze, 1899; Brown et al., 2009; Rinkevich et al., 2010; Jeffery, 2014; Kassmer et al., 2016; Zondag et al., 2016); however, ascidian tadpole larvae, which possess several vertebrate features, including a dorsal, hollow neural tube, do not regenerate during this early life stage (Jeffery, 2014).
and Haliclona sp., the coral Siderastrea stellata, and ascidian (Ascidiacea) collected at the states of Paraiba and Rio Grande do Norte, Northeastern Brazil.
According to the company, Plitidepsin is an investigational anticancer agent of marine origin, originally obtained from the ascidian Aplidium albicans.
Different bivalve, ascidian (tunicate) and polychaete species have been found to be the primary host for haplosporidian parasites.
Munoz, Clavaminols G-N, Six New Marine Sphingoids from the Mediterranean Ascidian Clavelina phlegraea, Tetrahedron, 65, 4384 (2009).
In this review, we will discuss the gene regulatory network in an ascidian, Ciona intestinalis.
Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells.
The ascidian has become the hot topic for research and development both at home and abroad for its numerous active agents with high activity.
Indole alkaloids from marine invertebrates have reported to be anti-inflammatory potentials; these include conicamin from tunicate [22], Lepadiformines A and B from ascidian [23] and aplysinopsintype compound from sponge Hyrtios erecta [24], manzamine from sponge [25], carteramine A from sponge [26], and ascidiathiazones A and B [27, 28] from ascidan.