The Collaborative International Dictionary of English v.0.48:

Garter \Gar"ter\, n. [OE. gartier, F. jarreti[`e]re, fr. OF.
   garet bend of the knee, F. jarret; akin to Sp. garra claw,
   Prov. garra leg. See Garrote.]
   1. A band used to prevent a stocking from slipping down on
      the leg.
      [1913 Webster]

   2. The distinguishing badge of the highest order of
      knighthood in Great Britain, called the Order of the
      Garter, instituted by Edward III.; also, the Order itself.
      [1913 Webster]

   3. (Her.) Same as Bendlet.
      [1913 Webster]

   Garter fish (Zool.), a fish of the genus Lepidopus,
      having a long, flat body, like the blade of a sword; the
      scabbard fish.

   Garter king-at-arms, the chief of the official heralds of
      England, king-at-arms to the Order of the Garter; -- often
      abbreviated to Garter.

   Garter snake (Zool.), one of several harmless American
      snakes of the genus Eut[ae]nia, of several species (esp.
      E. saurita and E. sirtalis); one of the striped
      snakes; -- so called from its conspicuous stripes of
      color.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Snake \Snake\, n. [AS. snaca; akin to LG. snake, schnake, Icel.
   sn[=a]kr, sn?kr, Dan. snog, Sw. snok; of uncertain origin.]
   (Zool.)
   Any species of the order Ophidia; an ophidian; a serpent,
   whether harmless or venomous. See Ophidia, and Serpent.
   [1913 Webster]

   Note: Snakes are abundant in all warm countries, and much the
         larger number are harmless to man.
         [1913 Webster]

   Blind snake, Garter snake, Green snake, King snake,
   Milk snake, Rock snake, Water snake, etc. See under
      Blind, Garter, etc.

   Fetich snake (Zool.), a large African snake (Python
      Sebae) used by the natives as a fetich.

   Ringed snake (Zool.), a common European columbrine snake
      (Tropidonotus natrix).

   Snake eater. (Zool.)
   (a) The markhoor.
   (b) The secretary bird.

   Snake fence, a worm fence (which see). [U.S.]

   Snake fly (Zool.), any one of several species of
      neuropterous insects of the genus Rhaphidia; -- so
      called because of their large head and elongated neck and
      prothorax.

   Snake gourd (Bot.), a cucurbitaceous plant (Trichosanthes
      anguina) having the fruit shorter and less snakelike than
      that of the serpent cucumber.

   Snake killer. (Zool.)
   (a) The secretary bird.
   (b) The chaparral cock.

   Snake moss (Bot.), the common club moss (Lycopodium
      clavatum). See Lycopodium.

   Snake nut (Bot.), the fruit of a sapindaceous tree
      (Ophiocaryon paradoxum) of Guiana, the embryo of which
      resembles a snake coiled up.

   Tree snake (Zool.), any one of numerous species of
      colubrine snakes which habitually live in trees,
      especially those of the genus Dendrophis and allied
      genera.
      [1913 Webster]

WordNet (r) 3.0 (2006):

garter snake
    n 1: any of numerous nonvenomous longitudinally-striped
         viviparous North American and Central American snakes [syn:
         garter snake, grass snake]