A ringtone is the sound your phone makes when someone calls you. Before cell phones, regular telephones made an actual ringing sound using a small hammer that struck metal bells inside the phone. Modern phones don't have bells, but they still play sounds to alert you to incoming calls, and we still call these sounds ringtones.

Early cell phones came with just a few simple beeping patterns, but now you can choose from thousands of options: songs, sound effects, or custom recordings. You might set your favorite song as your ringtone, or pick something funny that makes people smile when your phone goes off. Some people choose different ringtones for different callers so they know who's calling without looking at the screen.

The word can also refer to the actual audio file that creates the sound. When you download a ringtone, you're getting a short audio clip, usually 15 to 30 seconds long. Many ringtones use the catchiest part of a popular song, called the hook, so you'll recognize it immediately.

In the early 2000s, ringtones became a huge business, with people spending millions of dollars downloading them. Today most phones let you create custom ringtones for free from music you own.