Definition: "Mousemac" refers to a small, furry creature that can jump on ceilings or walls. The term was coined by a British author in 2004. "Mac" in this context generally means a computer system with an operating system (OS) running on it. So 'mousemac' is like a tiny little worm that has a mouse-like body and a human-like head, but is also capable of climbing ceilings or walls just like a mouse.