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
           forward

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "couchant":
   accumbent, couche, crawling, crouched, debased, decumbent,
   depressed, draped, flat, groveling, knee-high, knocked flat,
   laid low, lolling, lounging, low, low-built, low-hung, low-level,
   low-leveled, low-lying, low-set, low-statured, lying, neap,
   procumbent, prone, prostrate, reclining, recumbent, reposing,
   resupine, runty, short, sprawled, sprawling, spread, squat,
   squatty, stooped, stumpy, supine, unelevated



Bouvier's Law Dictionary, Revised 6th Ed (1856):

COUCHANT. Lying down. Animals are said to have been levant and couchant,
when they have been upon another person's land, damage feasant, one night at
least. 3 Bl. Com. 9.