The Collaborative International Dictionary of English v.0.48:

Gaiter \Gai"ter\, v. t.
   To dress with gaiters. Gaitre

The Collaborative International Dictionary of English v.0.48:

Gaiter \Gait"er\, n. [F. gu[^e]tre, cf. Armor. gweltren; or
   perh. of German origin, and akin to E. wear, v.]
   1. A covering of cloth or leather for the ankle and instep,
      or for the whole leg from the knee to the instep, fitting
      down upon the shoe.
      [1913 Webster]

   2. A kind of shoe, consisting of cloth, and covering the
      ankle.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gaiter
    n 1: a cloth covering (a legging) that covers the instep and
         ankles [syn: spat, gaiter]
    2: a shoe covering the ankle with elastic gores in the sides
    3: legging consisting of a cloth or leather covering for the leg
       from the knee to the ankle