The Collaborative International Dictionary of English v.0.48:

Tiller \Till"er\, n. [From Till, v. t.]
   One who tills; a husbandman; a cultivator; a plowman.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tiller \Till"er\, n. [AS. telgor a small branch. Cf. Till to
   cultivate.]
   1. (Bot.)
      (a) A shoot of a plant, springing from the root or bottom
          of the original stalk; a sucker.
      (b) A sprout or young tree that springs from a root or
          stump.
          [1913 Webster]

   2. A young timber tree. [Prov. Eng.] --Evelyn.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tiller \Till"er\, v. i. [imp. & p. p. Tillered; p. pr. & vb.
   n. Tillering.]
   To put forth new shoots from the root, or round the bottom of
   the original stalk; as, wheat or rye tillers; some spread
   plants by tillering. [Sometimes written tillow.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tiller \Till"er\, n. [From OE. tillen, tullen, to draw, pull;
   probably fr. AS. tyllan in fortyllan to lead astray; or cf.
   D. tillen to lift up. Cf. Till a drawer.]
   1. (Naut.) A lever of wood or metal fitted to the rudder head
      and used for turning side to side in steering. In small
      boats hand power is used; in large vessels, the tiller is
      moved by means of mechanical appliances. See Illust. of
      Rudder. Cf. 2d Helm, 1.
      [1913 Webster]

   2. The stalk, or handle, of a crossbow; also, sometimes, the
      bow itself. [Obs.]
      [1913 Webster]

            You can shoot in a tiller.            --Beau. & Fl.
      [1913 Webster]

   3. The handle of anything. [Prov. Eng.]
      [1913 Webster]

   4. A small drawer; a till. --Dryden.
      [1913 Webster]

   Tiller rope (Naut.), a rope for turning a tiller. In a
      large vessel it forms the connection between the fore end
      of the tiller and the steering wheel.
      [1913 Webster] Tilley

WordNet (r) 3.0 (2006):

tiller
    n 1: a shoot that sprouts from the base of a grass
    2: someone who tills land (prepares the soil for the planting of
       crops)
    3: lever used to turn the rudder on a boat
    4: a farm implement used to break up the surface of the soil
       (for aeration and weed control and conservation of moisture)
       [syn: cultivator, tiller]
    v 1: grow shoots in the form of stools or tillers [syn: stool,
         tiller]

Moby Thesaurus II by Grady Ward, 1.0:

49 Moby Thesaurus words for "tiller":
   Bauer, agriculturalist, agriculturist, agrologist, agronomist,
   coffee-planter, collective farm worker, crofter, cropper,
   cultivator, dirt farmer, dry farmer, farm laborer, farmer,
   farmhand, gentleman farmer, granger, grower, harvester, harvestman,
   haymaker, helm, husbandman, kibbutznik, kolkhoznik, kulak, muzhik,
   peasant, peasant holder, picker, planter, plowboy, plowman, raiser,
   rancher, ranchman, reaper, reins, reins of government, rudder,
   rustic, sharecropper, sower, tea-planter, tenant farmer,
   tree farmer, truck farmer, wheel, yeoman