"Hello, computer."
A computer mouse was a manual input device on computers of the 20th and 21st centuries. The device was known as a mouse because the cord which connected the device to the computer resembled the tail of a mouse. The user could manipulate computer via the mouse by sliding it around on a flat surface and clicking buttons.
Montgomery Scott mistook the device for an audio-input device when he traveled back in time to 1986, speaking into it when his attempts to talk directly to the computer were unsuccessful. (Star Trek IV: The Voyage Home)
Kathryn Janeway used a mouse to access Chronowerx Industries' database in 1996. (VOY: "Future's End")