Main Entry: tread·mill

Pronunciation: \ˈtred-ˌmil\

Function: noun

Date: 1822

1 a : a mill worked by persons treading on steps on the periphery of a wide wheel having a horizontal axis and used formerly in prison punishment b : a mill worked by an animal treading an endless belt c : a device having an endless belt on which an individual walks or runs in place for exercise or physiological testing
2 : a wearisome or monotonous routine resembling continued activity on a treadmill <the office treadmill>