Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
intumescency is a noun meaning "swelling up with blood or other fluids (as with congestion)". It carries 2 recorded senses.
swelling up with blood or other fluids (as with congestion)
the increase in volume of certain substances when they are heated (often accompanied by release of water)
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 intumescency come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.