Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
capaciousness is a noun meaning "intellectual breadth". It carries 2 recorded senses.
spatial largeness and extensiveness (especially inside a building)
“the capaciousness of Santa's bag astounded the child”
“roominess in this size car is always a compromise”
“his new office lacked the spaciousness that he had become accustomed to”
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 capaciousness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.