Melt/melt/ Definition 1 of 4Pro Tip 1/3Heat Required Most often, 'melt' involves heat to change a solid to liquid. The cheese will melt once you heat up the pizza. Pro Tip 2/3Natural Occurrence Melting can happen naturally, like with ice in warm weather. Watch the ice cubes melt on the sidewalk. Pro Tip 3/3Used Metaphorically Describes something losing form or structure, not always literal melting. Their defenses melted under the comedian's wit.