say it: VAY-pur
vapor is a noun meaning "a visible suspension in the air of particles of some substance". It carries 2 recorded senses.
a visible suspension in the air of particles of some substance
the process of becoming a vapor
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 vapor 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.