What is the difference between diapers and diaper pads?

Diapers can be worn directly on the baby's body, like underwear, diaper pads like sanitary napkins need a disposable paper pants to be fixed, diapers are a little bit better sealing, and diaper pads are more prone to side leakage. But you can't wear these two things to your baby often, and it's easy to get a red rash on your little butt.