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.
  Note: ☞ Laminaria is the common kelp of Great Britain; Macrocystis pyrifera and Nereocystis Lutkeana are the great kelps of the Pacific Ocean.
  Kelp crab Zool., a California spider crab (Epialtus productus), found among seaweeds, which it resembles in color.
  Kelp salmon Zool., a serranoid food fish (Serranus clathratus) of California. See Cabrilla.
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  Mac·ro·cys·tis n.  Bot. An immensely long blackish seaweed of the Pacific (Macrocystis pyrifera), having numerous almond-shaped air vessels.
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