Source : Webster's Revised Unabridged Dictionary (1913)

Carrageen \Car"ra*geen`\, Carrigeen \Car"ri*geen`\, n.
   A small, purplish, branching, cartilaginous seaweed
   ({Chondrus crispus}), which, when bleached, is the {Irish
   moss} of commerce. [Also written {carragheen}, {carageen}.]

Source : WordNet®

carrageen
     n : dark purple edible seaweed of the Atlantic coasts of Europe
         and North America [syn: {Irish moss}, {carageen}, {carragheen},
          {Chondrus crispus}]