Source : Webster's Revised Unabridged Dictionary (1913)

Holothurian \Hol`o*thu"ri*an\, a. (Zo["o]l.)
   Belonging to the Holothurioidea. -- n. One of the
   Holothurioidea.

   Note: Some of the species of Holothurians are called {sea
         cucumbers}, {sea slugs}, {trepang}, and {b[^e]che de
         m[`e]r}. Many are used as food, esp. by the Chinese.
         See {Trepang}.

Source : WordNet®

holothurian
     n : echinoderm having a flexible sausage-shaped body, tentacles
         surrounding the mouth and tube feet; free-living mud
         feeders: sea cucumbers [syn: {sea cucumber}]