Kelp

n.
  1. The calcined ashes of seaweed, -- formerly much used in the manufacture of glass, now used in the manufacture of iodine.
  2. (Bot.) Any large blackish seaweed.
    3. Kelp crab (Zoöl.),
    a California spider crab (Epialtus productus), found among seaweeds, which it resembles in color.
    Kelp salmon (Zoöl.),
    a serranoid food fish (Serranus clathratus) of California. See Cabrilla.