(mice)
Note: The plural '~s' can be used for meaning 2.
1.
A ~ is a small furry animal with a long tail.
...a ~ running in a wheel in its cage.
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2.
A ~ is a device that is connected to a computer. By moving it over a flat surface and pressing its buttons, you can move the cursor around the screen and do things without using the keyboard.
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3.
game of cat and ~: see cat