Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
miasm is a noun meaning "an unwholesome atmosphere". It carries 2 recorded senses.
an unwholesome atmosphere
“the novel spun a miasma of death and decay”
unhealthy vapors rising from the ground or other sources
“the miasma of the marshes”
“a miasma of cigar smoke”
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 miasm come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.