os /ˈɑs/
 骨,孔,穴裂口
 Os n.; pl. Ossa   A bone.
 Os, n.; pl. Ora   A mouth; an opening; an entrance.
 Os n.; pl. Osar   Geol. One of the ridges of sand or gravel found in Sweden, etc., supposed by some to be of marine origin, but probably formed by subglacial waters.  The osar are similar to the kames of Scotland and the eschars of Ireland.  See Eschar.
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 os
      n 1: a mouth or mouthlike opening
      2: a hard brittle blue-gray or blue-black metallic element that
         is one of the platinum metals; the heaviest metal known
         [syn: osmium, atomic number 76]
      3: (computer science) software that controls the execution of
         computer programs and may provide various services [syn: operating
         system]
      4: the left eye [syn: oculus sinister]
      5: rigid connective tissue that makes up the skeleton of
         vertebrates [syn: bone]
      [also: ossa (pl), osar (pl), ora (pl)]