What is what does it mean when it says call is waiting?

When it says that a call is waiting, it means that someone is trying to call you while you are already on the phone with another person. If your phone is compatible with call waiting, you will hear a beep or a tone indicating that there is another incoming call. You can switch between the calls by putting the first caller on hold and then answering the second call. Alternatively, you can choose to ignore the second call and let it go to voicemail. Call waiting is a useful feature that allows you to manage multiple calls and not miss important calls while you are already on the phone.