treadmill

American  

[tred-mil] / ˈtrɛdˌmɪl /

noun

1. an apparatus for producing rotary motion by the weight of people or animals, treading on a succession of moving steps or a belt that forms a kind of continuous path, as around the periphery of a pair of horizontal cylinders.

2. an exercise machine that allows the user to walk or run in place, usually on a continuous moving belt.

3. any monotonous, wearisome routine in which there is little or no satisfactory progress.

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treadmill British  

/ ˈtrɛdˌmɪl /

noun

1. Also called: treadwheel.  (formerly) an apparatus used to produce rotation, in which the weight of men or animals climbing steps on or around the periphery of a cylinder or wheel caused it to turn

2. a dreary round or routine

3. an exercise machine that consists of a continuous moving belt on which to walk or jog

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Etymology

Origin of treadmill

First recorded in 1815–25; tread + mill ¹

Explanation

A treadmill is an exercise machine for walking or running in place. If it's bitterly cold outside, you might decide to go to the gym and run on the treadmill instead of taking your usual outdoor jog. A treadmill was originally a type of human- or animal-powered machine. By walking on a wheel fitted with steps, a person (or animal) turned it, grinding grain in the process. Treadmills were also used as punishment in prisons where inmates were forced to work. Today the only treadmills you're likely to see are in a gym, but the word is commonly used in a figurative way for any relentless, boring job.

Example Sentences

Researchers evaluated them using several measures, including grip strength, walking speed, treadmill endurance, and overall energy levels.

From Science Daily • May 19, 2026

“They already have the standing desks, the treadmill walks, but the scans and assessments help them realize they need to strengthen their lower body,” Thompson says.

From The Wall Street Journal • May 16, 2026

From my treadmill desk, I attend “Overwhelmed and Burnt Out,” also known as “Burnout Circle,” a 45-minute Zoom meeting led by a Good Inside counselor.

From Slate • May 10, 2026

They were asked to do supervised, brisk-walking exercise sessions on a treadmill for 40 minutes a day, five times a week for three months.

From BBC • Apr. 14, 2026

All of life was like running on a treadmill.

From "My Brother Sam is Dead" by James Lincoln Collier and Christopher Collier