Noun

(en noun)

A piece of indoor sporting equipment used to allow for the motions of running or walking while staying in one place.

A mill worked by persons treading upon steps on the periphery of a wide wheel having a horizontal axis. It is used principally as a means of prison discipline.

A mill worked by horses, dogs, etc., treading an endless belt.

*{{quote-magazine, year=2013, month=July-August, author=(Henry Petroski)

, title= Geothermal Energy , volume=101, issue=4, magazine=(American Scientist) , passage=Ancient nomads, wishing to ward off the evening chill and enjoy a meal around a campfire, had to collect wood and then spend time and effort coaxing the heat of friction out from between sticks to kindle a flame. With more settled people, animals were harnessed to capstans or caged in treadmills to turn grist into meal.}}