\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.

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