To chase means to run after someone or something, trying to catch them or make them go away. When a dog chases a squirrel up a tree, it's running as fast as it can, hoping to catch it. When kids play tag, they chase each other around the playground. Police officers might chase a suspect who's running from the scene of a crime.

The word implies speed, effort, and purpose. You might follow your teacher down the hallway at a normal walking pace, but you'd chase your friend who grabbed your hat and took off running.

Chase can also mean pursuing a goal or dream with determination. An athlete might chase an Olympic medal by training for years. A scientist might spend decades chasing the answer to a difficult question. When someone says “chase your dreams,” they mean work hard to achieve what matters most to you.

You can also chase away something unwanted, like when a farmer chases crows away from crops, or when you chase away worries by doing something fun. A wild goose chase means pursuing something impossible to catch, wasting time and energy on a hopeless task.

As a noun, a chase is the act of chasing: a fast pursuit. In a movie, a car chase is a scene where one vehicle races after another.