The tiller is what steers a boat specifically, the handle attached to the rudder. Tillers are generally found on smaller boats because it would take too much force to steer larger ships with hand tillers.
One who tills; a husbandman; a cultivator; a plowman.
Noun
 a farm implement used to break up the surface of the soil (for aeration and weed control and conservation of moisture)
Noun
 lever used to turn the rudder on a boat
Noun
 someone who tills land (prepares the soil for the planting of crops)
Noun
 a shoot that sprouts from the base of a grass
Verb
 grow shoots in the form of stools or tillers
v. t.
 One who tills; a husbandman; a cultivator; a plowman.
n.
 A shoot of a plant, springing from the root or bottom of
   the original stalk; a sucker.
n.
 A sprout or young tree that springs from a root or stump.
n.
 A young timber tree.
v. i.
 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.
n.
 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.
n.
 The stalk, or handle, of a crossbow; also, sometimes, the
   bow itself.
n.
 The handle of anything.
n.
 A small drawer; a till.
Tiller
Tiller
Tiller
Tiller
You can shoot in a tiller.3.
One who tills; a husbandman; a cultivator; a plowman.
A shoot of a plant, springing from the root or bottom of the original stalk; a sucker.
To put forth new shoots from the root, or round the bottom of the original stalk; 
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 
Usage Examples
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