A growl is a low, rumbling, threatening sound that comes from deep in the throat. When a dog growls, it's warning you to back off, showing its teeth and making that deep, rough noise that says “Don't come closer.” Bears, lions, and wolves all growl when they feel threatened or want to protect their territory.

The word can also describe similar sounds that aren't from animals. Your stomach might growl when you're hungry, making those gurgling noises that everyone can hear during a quiet moment in class. An old car engine might growl as it struggles to start on a cold morning.

People growl too, though not exactly like animals. When someone growls a response, they speak in a low, harsh, irritated voice. A frustrated coach might growl at players who aren't paying attention: “I said run three laps, not two!” It's not quite yelling, but it carries that same grumpy, warning tone that tells you someone's patience is wearing thin. The sound itself tells you a lot: stay alert, something's unhappy, and you should be careful about what you do next.