Steerable means able to be guided or directed where you want it to go. A bicycle is steerable because you can turn the handlebars to change direction. A remote-control car is steerable because you can make it go left, right, or straight ahead.

Ships have steering wheels that turn the rudder underwater. Airplanes have controls that make them steerable in three dimensions: left, right, up, and down. Even shopping carts are steerable, though anyone who's wrestled with one that has a wobbly wheel knows some things are more steerable than others.

When engineers design vehicles or machines, steerability matters enormously. A skateboard is somewhat steerable through shifting your weight, but not nearly as precisely steerable as a bicycle with handlebars. Modern cars use power steering to make them easily steerable even at slow speeds, when turning the wheel would otherwise require significant strength.

Scientists also use “steerable” to describe things like telescope dishes that can be pointed at different parts of the sky, or spotlights that can be aimed in different directions. Anything that can be controlled and redirected rather than just moving in a fixed path can be called steerable.