Chapstick is a brand of lip balm, but it's what everyone calls any kind of lip balm, regardless of if it's Chapstick, Blistex, or whatnot.

Chapstick is a waxy substance that comes in a tube. You can apply it to your lips if they're chapped and they might get better. If they aren't chapped, then you can still apply it to your lips for the great taste.