Unmelted means not melted, or still in solid form when you'd expect it to have melted. When ice cubes sit in your glass of lemonade and stay frozen instead of turning to water, they're unmelted. When chocolate chips in cookies keep their shape instead of spreading into gooey pools, they remain unmelted.

The word often appears when something resists melting longer than expected. You might find unmelted snow in a shady spot long after the sunny patches have turned to slush. A scoop of ice cream might have an unmelted center even when the outside has started to soften.

Scientists use this word too. A geologist studying lava might examine unmelted rock fragments, or a chemist might work with unmelted wax. The word simply describes the state of being solid when melting was possible or expected, but didn't happen.