The Collaborative International Dictionary of English v.0.48:

Horseflesh \Horse"flesh`\, n.
   1. The flesh of horses.

   Syn: horsemeat.
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              The Chinese eat horseflesh at this day. --Bacon.
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   2. Horses, generally; the qualities of a horse; as, he is a
      judge of horseflesh. [Colloq.]
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   Horseflesh ore (Min.), a miner's name for bornite, in
      allusion to its peculiar reddish color on fresh facture.
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WordNet (r) 3.0 (2006):

horseflesh
    n 1: the flesh of horses as food [syn: horsemeat,
         horseflesh]