Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
ascus is a noun meaning "saclike structure in which ascospores are formed through sexual reproduction of ascomycetes". It carries one recorded sense.
saclike structure in which ascospores are formed through sexual reproduction of ascomycetes
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 ascus come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.