Noun
any nocturnal Old World mouse of the genus Apodemus inhabiting woods and fields and gardens
any of various small mouselike rodents of the family Cricetidae (especially of genus Microtus) having a stout short-tailed body and inconspicuous ears and inhabiting fields or meadows
Source: WordNetfield-mouse
Subgenera Field mouse of the subgenus Mus All members of the Mus genus are referred to as mice. Source: Internet