Search Result for "sea urchin":
Wordnet 3.0

NOUN (1)

1. shallow-water echinoderms having soft bodies enclosed in thin spiny globular shells; 



The Collaborative International Dictionary of English v.0.48:

Sea urchin \Sea" ur"chin\ (Zool.)
   Any one of numerous species of echinoderms of the order
   Echinoidea.

   Note: When living they are covered with movable spines which
         are often long and sharp.
         [1913 Webster]


WordNet (r) 3.0 (2006):

sea urchin
    n 1: shallow-water echinoderms having soft bodies enclosed in
         thin spiny globular shells