A leash is a rope, cord, or strap that connects to a dog's collar so you can keep your pet close and under control when walking outside. When you take a dog for a walk, you clip one end of the leash to the collar and hold the other end in your hand. This way, your dog can't run into traffic, chase squirrels across the street, or jump on strangers who might not appreciate an enthusiastic greeting.

Most towns and cities have leash laws requiring dogs to be on leashes in public places. This protects both the dog and other people. Even the friendliest dog might get startled and run away, or encounter another dog that isn't friendly.

The word also appears in expressions about control. When someone says a person is being kept “on a short leash,” they mean that person isn't being given much freedom or independence. A student whose parents check every homework assignment and monitor every activity might feel they're on a short leash. Conversely, when you're given a longer leash, you're being trusted with more freedom to make your own choices.

People also use leashes for other animals, and surfers attach leashes from their ankles to their surfboards so the board doesn't drift away after a wipeout.