Source : Webster's Revised Unabridged Dictionary (1913)

Fucoid \Fu"coid\, a. [Fucus + -oid.] (Bot.)
   (a) Properly, belonging to an order of alga: ({Fucoide[ae]})
       which are blackish in color, and produce o["o]spores
       which are not fertilized until they have escaped from the
       conceptacle. The common rockweeds and the gulfweed
       ({Sargassum}) are fucoid in character.
   (b) In a vague sense, resembling seaweeds, or of the nature
       of seaweeds.

Fucoid \Fu"coid\, n. (Bot.)
   A plant, whether recent or fossil, which resembles a seaweed.
   See {Fucoid}, a.

Source : WordNet®

fucoid
     n 1: a fossilized cast or impression of algae of the order
          Fucales
     2: any of various algae of the family Fucaceae [syn: {fucoid
        algae}]