say it: POW-ur-hows
powerhouse is a noun meaning "a highly energetic and indefatigable person". It carries 3 recorded senses.
a highly energetic and indefatigable person
a team considered to be the best of its class
an electrical generating station
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 powerhouse 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.