Definition from Wiktionary, the free dictionary
treadmill (plural treadmills)
- 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.
2013 July-August, Henry Petroski, “Geothermal Energy”, in American Scientist, volume 101, number 4:
- 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.
piece of indoor sporting equipment
mill worked by persons