costa
    n 1: a riblike part of a plant or animal (such as a middle rib
         of a leaf or a thickened vein of an insect wing)
    2: any of the 12 pairs of curved arches of bone extending from
       the spine to or toward the sternum in humans (and similar
       bones in most vertebrates) [syn: rib, costa]

Costa \Cos"ta\ (k[o^]s"t[.a]), n. [L., rib. See Coast.]
   1. (Anat.) A rib of an animal or a human being.
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   2. (Bot.) A rib or vein of a leaf, especially the midrib.
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   3. (Zool.)
      (a) The anterior rib in the wing of an insect.
      (b) One of the riblike longitudinal ridges on the exterior
          of many corals.
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