tread
     n 1: a step in walking or running [syn: {pace}, {stride}]
     2: the grooved surface of a pneumatic tire
     3: the part (as of a wheel or shoe) that makes contact with the
        ground
     4: structural member consisting of the horizontal part of a
        stair or step
     v 1: put down or press the foot, place the foot; "For fools rush
          in where angels fear to tread"; "step on the brake"
          [syn: {step}]
     2: tread or stomp heavily or roughly; "The soldiers trampled
        across the fields" [syn: {trample}]
     3: crush as if by treading on; "tread grapes to make wine"
     4: brace (an archer's bow) by pressing the foot against the
        center
     5: apply (the tread) to a tire
     6: mate with; "male birds tread the females"
     [also: {trodden}, {trod}]
Source: WordNet® 2.0