Is mice plural?

Yes, mice is plural, it is the irregular plural form of the singular noun mouse. In English, most nouns form the plural by adding s or es, like cat to cats or box to boxes, but mouse is one of a small group of irregular nouns that change the vowel instead. So one mouse becomes two or more mice. This applies to both meanings of mouse, the small rodent Mus musculus that lives in houses and fields, and the computer pointing device used to control a cursor. For example, you would say I saw one mouse in the pantry and I saw several mice in the pantry, or I have one computer mouse at home and the office has twenty computer mice, although some people informally say computer mouses, the traditional correct plural remains mice. You would never say mices, which is incorrect, or use mice to refer to a single animal. The plural verb form goes with mice, for example the mice are hiding in the wall, not the mice is hiding. Other similar irregular plurals include louse to lice, goose to geese, man to men, and foot to feet. So if you are writing or speaking, remember mouse is singular and mice is always plural.