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What is the plural of 'mouse' on a computer? mice or mouse?
MOUSE is an acronym, and is short for Manually-Operated User-Selection Equipment so technically MOUSE is already the plural (... Equipments?) Most people, however pluralize acronyms, and initials in general, by adding a small s, so it would be MOUSEs, which seems a bit silly. Mice is also wrong, as it doesn't stand for anything.
English Language Institute ~ Missouri State University