はつかねずみMeaningsNoun1. house mouse (Mus musculus) (Usually kana)Other spellings二十日はつか鼠ねずみUsually written in kanaOther readingsハツカネズミKanji in other spellings二two十ten日sun鼠mousePitch accentはつかねずみExamples1ハツカネズミとドブネズミは異ことなる。Mice are distinct from rats.