say it: MUH-stur
muster is a noun and verb meaning "a gathering of military personnel for duty". It carries 4 recorded senses.
a gathering of military personnel for duty
“he was thrown in the brig for missing muster”
military
compulsory military service
military
call to duty, military service, jury duty, etc.
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 muster 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.