*mousetrap*

n. Any device that catches, and usually kills, mice. They are of various designs, the most common being a stiff loop of wire mounted on a small wooden platform base and attached to a strong spring, which holds the loop firmly against the base. To activate the trap, the loop is pulled through a 180° arc against the tension of the spring and held against the base by a delicate metal catch, which can keep the loop from moving, though in a state of high tension. The metal catch is moved when a mouse tries to take a piece of bait attached to it, releasing the loop which forcefully moves though an arc, usually killing the mouse. A larger version of the same device is used as a rat trap. [ 1913 Webster ]