Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
fieldmouse is a noun meaning "any nocturnal Old World mouse of the genus Apodemus inhabiting woods and fields and gardens". It carries one recorded sense.
any nocturnal Old World mouse of the genus Apodemus inhabiting woods and fields and gardens
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 fieldmouse come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.