The Collaborative International Dictionary of English v.0.48:

Rut \Rut\, n. [F. rut, OF. ruit, L. rugitus a roaring, fr.
   rugire to roar; -- so called from the noise made by deer in
   rutting time.]
   1. (Physiol.) Sexual desire or oestrus of deer, cattle, and
      various other mammals; heat; also, the period during which
      the oestrus exists.
      [1913 Webster]

   2. Roaring, as of waves breaking upon the shore; rote. See
      Rote.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rut \Rut\, v. i. [imp. & p. p. Rutted; p. pr. & vb. n.
   Rutting.]
   To have a strong sexual impulse at the reproductive period;
   -- said of deer, cattle, etc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rut \Rut\, v. t.
   To cover in copulation. --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rut \Rut\, n. [variant of route.]
   A track worn by a wheel or by habitual passage of anything; a
   groove in which anything runs. Also used figuratively.
   [1913 Webster]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rut \Rut\, v. t.
   To make a rut or ruts in; -- chiefly used as a past
   participle or a participial adj.; as, a rutted road.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rut
    n 1: a groove or furrow (especially one in soft earth caused by
         wheels)
    2: a settled and monotonous routine that is hard to escape;
       "they fell into a conversational rut" [syn: rut, groove]
    3: applies to nonhuman mammals: a state or period of heightened
       sexual arousal and activity [syn: estrus, oestrus,
       heat, rut] [ant: anestrum, anestrus, anoestrum,
       anoestrus]
    v 1: be in a state of sexual excitement; of male mammals
    2: hollow out in the form of a furrow or groove; "furrow soil"
       [syn: furrow, rut, groove]

Moby Thesaurus II by Grady Ward, 1.0:

120 Moby Thesaurus words for "rut":
   alameda, be in heat, beat, beaten path, beaten track, berm, bezel,
   bicycle path, boardwalk, bridle path, bureaucracy, bureaucratism,
   canal, canalize, carve, catwalk, chamfer, channel, chase, chink,
   chinoiserie, chisel, chuckhole, come in, corrugate, corrugation,
   crack, cranny, crimp, cut, dado, daily grind, desire, dike, ditch,
   engrave, engraving, esplanade, estral cycle, estruate, estruation,
   estrum, estrus, fastwalk, fever, fever heat, fever of excitement,
   fire, flute, fluting, foot pavement, footpath, footway, furrow,
   fury of lust, garden path, gash, goffer, gouge, grind, groove,
   gully, heat, hiking trail, incise, incision, itch for, jog trot,
   lust, lust after, mall, microgroove, mudhole, pace, parade, path,
   pathway, pitchhole, pleat, plow, pothole, prado, promenade,
   public walk, rabbet, red tape, red-tapeism, rifle, rifling, rote,
   round, routine, ruck, run, runway, score, scratch,
   sexual excitement, sidewalk, sinkhole, slit, squirrel cage, streak,
   stria, striate, striation, sulcation, sulcus, towing path, towpath,
   track, trail, treadmill, trench, trottoir, trough, walk, walkway,
   well-worn groove, wrinkle