say it: TRED-mil
treadmill is a noun meaning "an exercise device consisting of an endless belt on which a person can walk or jog without changing place". It carries 3 recorded senses.
an exercise device consisting of an endless belt on which a person can walk or jog without changing place
a mill that is powered by men or animals walking on a circular belt or climbing steps
a job involving drudgery and confinement
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for treadmill come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.