say it: kee-moh-THER-uh-pee
chemotherapy is a noun meaning "the use of chemical agents to treat or control disease (or mental illness)". It carries one recorded sense.
the use of chemical agents to treat or control disease (or mental illness)
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 chemotherapy 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.