The Collaborative International Dictionary of English v.0.48:

Lozenge \Loz"enge\ (l[o^]z"[e^]nj), n. [F. lozange, losange;
   perh. the same as OF. losengef flattery, praise, the heraldic
   sense being the oldest (cf. E. hatchment, blazon). Cf.
   Losenger, Laudable.]
   1. (Her.)
      (a) A diamond-shaped figure usually with the upper and
          lower angles slightly acute, borne upon a shield or
          escutcheon. Cf. Fusil.
      (b) A form of the escutcheon used by women instead of the
          shield which is used by men.
          [1913 Webster]

   2. A figure with four equal sides, having two acute and two
      obtuse angles; a rhomb.
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   3. Anything in the form of lozenge.
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   4. Specifically: A small cake of sugar and starch, flavored,
      and often medicated. -- originally in the form of a
      lozenge.
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   Lozenge coach, the coach of a dowager, having her coat of
      arms painted on a lozenge. [Obs.] --Walpole.

   Lozenge-molding (Arch.), a kind of molding, used in Norman
      architecture, characterized by lozenge-shaped ornaments.
      [1913 Webster] Lozenged