Why do they call commercial music jingles?

Jingles are short, memorable musical pieces used in advertising to help create brand recognition and recall. Jingles are typically used to accompany visual advertisements, such as television commercials or radio ads. They are designed to be catchy and easy to remember, so that they will stick in the listener's mind and associate with the advertised product or service. They're called "jingles" because they produce a ringing sound in people's ears and memories, which is the most common feature that makes it easy for people to remember them.