The Collaborative International Dictionary of English v.0.48:

Couchant \Couch"ant\ (kouch"ant), a. [F., p. pr. of coucher. See
   Couch, v. t.]
   1. Lying down with head erect; squatting.
      [1913 Webster]

   2. (Her.) Lying down with the head raised, which
      distinguishes the posture of couchant from that of
      dormant, or sleeping; -- said of a lion or other beast.
      [1913 Webster]

   Couchant and levant (Law), rising up and lying down; --
      said of beasts, and indicating that they have been long
      enough on land, not belonging to their owner, to lie down
      and rise up to feed, -- such time being held to include a
      day and night at the least. --Blackstone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

couchant
    adj 1: lying on the stomach with head raised with legs pointed
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