Umbo

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Umbo \Um"bo\, n.; pl. L. {Umbones}, E. {Umbos}. [L.]
     1. The boss of a shield, at or near the middle, and usually
        projecting, sometimes in a sharp spike.
        [1913 Webster]
  
     2. A boss, or rounded elevation, or a corresponding


        depression, in a palate, disk, or membrane; as, the umbo
        in the integument of the larvae of echinoderms or in the
        tympanic membrane of the ear.
        [1913 Webster]
  
     3. (Zool.) One of the lateral prominences just above the
        hinge of a bivalve shell.
        [1913 Webster] Umbonate

From WordNet (r) 2.0 [wn]:

  umbo
       n : a slight rounded elevation where the malleus attaches to the
           eardrum
       [also: {umbones} (pl)]