Tread  —v. (past trod; past part. Trodden or trod) 1 (often foll. By on) set down one's foot; walk, step. 2 a walk on. B (often foll. By down) press or crush with the feet. 3 perform (steps etc.) By walking. 4 (often foll. By in, into) press down into the ground with the feet (trod dirt into the carpet). —n. 1 manner or sound of walking. 2 top surface of a step or stair. 3 thick moulded part of a vehicle tyre for gripping the road. 4 a part of a wheel that touches the ground or rail. B part of a rail that the wheels touch. 5 part of the sole of a shoe that rests on the ground.  tread the boards be an actor. Tread on air feel elated. Tread on a person's toes offend a person; encroach on a person's privileges etc. Tread water maintain an upright position in water by moving the feet and hands. [old english]