say it: ri-ZURVZ
reserves is a noun meaning "civilians trained as soldiers but not part of the regular army". It carries one recorded sense.
civilians trained as soldiers but not part of the regular army
military
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 reserves 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.