To curb something means to hold it back or keep it under control. When you curb your excitement about an upcoming field trip, you're trying not to bounce off the walls even though you're thrilled inside. A teacher might need to curb the noise level in a cafeteria that's getting too loud.

The word often describes controlling something that wants to grow or spread: a city might try to curb pollution, or a coach might curb a team's overconfidence before a big game. Think of it like gently pulling back on the reins of a horse that wants to gallop when you need it to walk.

Curb is also a noun for the raised edge where a sidewalk meets the street. When you're told to wait at the curb for your ride, you stand right at that concrete border. People also say kick it to the curb, meaning to get rid of something completely, like tossing trash into a bin (not into the street).