What does "keel" mean?

Keel: (Shipbuilding) A longitudinal timber, or series of timbers scarfed together, extending from stem to stern along the bottom of a vessel. It is the principal timber of the vessel, and, by means of the ribs attached on each side, supports the vessel's frame. In an iron vessel, a combination of plates supplies the place of the keel of a wooden ship. See Illust. of Keelson.

Additional senses

  1. 2.Fig.: The whole ship.
  2. 3.A barge or lighter, used on the Type for carrying coal from Newcastle; also, a barge load of coal, twentyone tons, four cwt. [Eng.]
  3. 4.(Bot.) The two lowest petals of the corolla of a papilionaceous flower, united and inclosing the stamens and pistil; a carina. See Carina.
  4. 5.(Nat. Hist.) A projecting ridge along the middle of a flat or curved surface. Bilge keel (Naut.), a keel peculiar to ironclad vessels, extending only a portion of the length of the vessel under the bilges. Ham. Nav. Encyc. -- False keel. See under False. -- Keel boat. (a) A covered freight boat, with a keel, but no sails, used on Western rivers. [U. S.] (b) A low, flat-bottomed freight boat. See Keel, n., 3. -- Keel piece, one of the timbers or sections of which a keel is composed. On even keel, in a level or horizontal position, so that the draught of water at the stern and the bow is the same. Ham. Nav. Encyc.
  5. 6.To traverse with a keel; to navigate.
  6. 7.To turn up the keel; to show the bottom. To keel over, to upset; to capsize. [Colloq.]

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