keyhole limpet

keyhole limpet
    n 1: marine limpet having a conical shell with an opening at the
         apex [syn: {keyhole limpet}, {Fissurella apertura},
         {Diodora apertura}]
    

Keyhole \Key"hole`\, n.
   1. A hole or apertupe in a door or lock, for receiving a key.
      [1913 Webster]

   2.
      (a) (Carp.) A hole or excavation in beams intended to be
          joined together, to receive the key which fastens
          them.
      (b) (Mach.) a mortise for a key or cotter.
          [1913 Webster]

   {Keyhole limpet} (Zool.), a marine gastropod of the genus
      Fissurella and allied genera. See {Fissurella}.

   {Keyhole saw}, a narrow, slender saw, used in cutting
      keyholes, etc., as in doors; a kind of compass saw or fret
      saw.

   {Keyhole urchin} (Zool.), any one of numerous clypeastroid
      sea urchins, of the genera {Melitta}, {Rotula}, and
      {Encope}; -- so called because they have one or more
      perforations resembling keyholes.
      [1913 Webster]
    

Fissurella \Fis`su*rel"la\, n. [NL., dim. of L. fissura a
   fissure.] (Zool.)
   A genus of marine gastropod mollusks, having a conical or
   limpetlike shell, with an opening at the apex; -- called also
   {keyhole limpet}.
   [1913 Webster]