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See sea squirt.
[From New Latin Ascidia, genus name, from Greek askidion, diminutive of askos, wineskin.]
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
as•cid•i•an(əˈsɪd i ən)
1. any tunicate of the class Ascidiacea, having in the larval stage a notochord, a characteristic of the embryonic vertebrate.adj.
2. belonging or pertaining to the class Ascidiacea.
[1855–60; < New Latin Ascidi(um) a tunicate genus < Greek askídion a small bag + -an1]
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|Noun||1.||ascidian - 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
sea squirt - ascidian that can contract its body and eject streams of water