The Collaborative International Dictionary of English v.0.48:

Stool \Stool\, n. [L. stolo. See Stolon.] (Hort.)
   A plant from which layers are propagated by bending its
   branches into the soil. --P. Henderson.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stool \Stool\, v. i. (Agric.)
   To ramfy; to tiller, as grain; to shoot out suckers. --R. D.
   Blackmore.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stool \Stool\, n. [AS. st[=o]l a seat; akin to OFries. & OS.
   st[=o]l, D. stoel, G. stuhl, OHG. stuol, Icel. st[=o]ll, Sw.
   & Dan. stol, Goth. st[=o]ls, Lith. stalas a table, Russ.
   stol'; from the root of E. stand. [root]163. See Stand, and
   cf. Fauteuil.]
   1. A single seat with three or four legs and without a back,
      made in various forms for various uses.
      [1913 Webster]

   2. A seat used in evacuating the bowels; hence, an
      evacuation; a discharge from the bowels.
      [1913 Webster]

   3. A stool pigeon, or decoy bird. [U. S.]
      [1913 Webster]

   4. (Naut.) A small channel on the side of a vessel, for the
      dead-eyes of the backstays. --Totten.
      [1913 Webster]

   5. A bishop's seat or see; a bishop-stool. --J. P. Peters.
      [1913 Webster]

   6. A bench or form for resting the feet or the knees; a
      footstool; as, a kneeling stool.
      [1913 Webster]

   7. Material, such as oyster shells, spread on the sea bottom
      for oyster spat to adhere to. [Local, U.S.]
      [1913 Webster]

   Stool of a window, or Window stool (Arch.), the flat
      piece upon which the window shuts down, and which
      corresponds to the sill of a door; in the United States,
      the narrow shelf fitted on the inside against the actual
      sill upon which the sash descends. This is called a window
      seat when broad and low enough to be used as a seat.

   Stool of repentance, the cuttystool. [Scot.]

   Stool pigeon, a pigeon used as a decoy to draw others
      within a net; hence, a person used as a decoy for others.
      [1913 Webster]

WordNet (r) 3.0 (2006):

stool
    n 1: a simple seat without a back or arms
    2: solid excretory product evacuated from the bowels [syn:
       fecal matter, faecal matter, feces, faeces, BM,
       stool, ordure, dejection]
    3: (forestry) the stump of a tree that has been felled or headed
       for the production of saplings
    4: a plumbing fixture for defecation and urination [syn:
       toilet, can, commode, crapper, pot, potty,
       stool, throne]
    v 1: lure with a stool, as of wild fowl
    2: react to a decoy, of wildfowl
    3: grow shoots in the form of stools or tillers [syn: stool,
       tiller]
    4: have a bowel movement; "The dog had made in the flower beds"
       [syn: stool, defecate, shit, take a shit, take a
       crap, ca-ca, crap, make]

Moby Thesaurus II by Grady Ward, 1.0:

115 Moby Thesaurus words for "stool":
   BM, babble, be indiscreet, be unguarded, bear witness against,
   bedpan, betray, betray a confidence, betrayer, blab, blabber,
   bloody flux, blow the whistle, blurt, blurt out, bowel movement,
   buffalo chips, ca-ca, can, canary, catharsis, chamber, chamber pot,
   chemical closet, chemical toilet, commode, coprolite, coprolith,
   cow chips, cow flops, cow pats, crap, crapper, defecate,
   defecation, dejection, diarrhea, dingleberry, droppings, dung,
   dysentery, evacuate, evacuation, feces, feculence, fink, flux,
   give away, guano, inform, inform against, inform on, jakes, jerry,
   john, johnny, jordan, latrine, leak, let drop, let fall, let slip,
   lientery, loose bowels, manure, movement, narc, nark, night soil,
   number two, ordure, peach, pimp, piss pot, potty, potty-chair,
   purgation, purge, rat, reveal a secret, runs, sell out, sewage,
   sewerage, shit, shits, sing, snitch, snitch on, spill,
   spill the beans, squeak, squeal, squealer, stool pigeon,
   take a shit, talk, tattle, tattle on, tell on, tell secrets,
   tell tales, testify against, throne, thunder mug, tipster, toilet,
   trots, turd, turistas, turn informer, urinal, void, voidance,
   water closet