Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
trigeminus is a noun meaning "the main sensory nerve of the face and motor nerve for the muscles of mastication". It carries one recorded sense.
the main sensory nerve of the face and motor nerve for the muscles of mastication
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 trigeminus come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.