1. To turn from a solid into a liquid in the presence of high temperatures or inside of something that is very hot. They should have known an ice sculpture would melt in this heat! My chocolate bar melted in the car.

2. To be very uncomfortable and produce a lot of sweat because of high temperatures or a source thereof. I feel like I'm melting in this weather—let's go to the pool to cool off. My parents are coming from Toronto to visit me in Texas—they're going to melt in this heat!