the convergence of two parallel railroad tracks in a narrow place; the inner rails cross and run parallel and then diverge so a train remains on its own tracks at all times
any of numerous small rodents typically resembling diminutive rats having pointed snouts and small ears on elongated bodies with slender usually hairless tails
a hand-operated electronic device that controls the coordinates of a cursor on your computer screen as you move it around on a pad; on the bottom of the device is a ball that rolls on the surface of the pad; "a mouse takes much more room than a trackball"