tread

verb (past trod /träd, träd/; past participle trodden /ˈträdn/ or trod)

• walk in a specified way:he trod lightly, trying to make as little contact with the mud as possible figurativethe administration had to tread carefully so as not to offend the judiciary
• (tread on) set one’s foot down on top of.
• [with object] walk on or along:shoppers will soon be treading the floors of the new shopping mall
• [with object] press down into the ground or another surface with the feet:food and cigarette butts had been trodden into the carpet
• [with object] crush or flatten something with the feet:the snow had been trodden down by the horses (as adjective trodden)she stood on the floor of trodden earth

noun

• 1 [in singular] a manner or the sound of someone walking:I heard the heavy tread of Dad’s boots

• 2the top surface of a step or stair.

• 3the thick molded part of a vehicle tire that grips the road.
• the part of a wheel that touches the ground or rail.
• the upper surface of a railroad track, in contact with the wheels.
• the part of the sole of a shoe that rests on the ground.