Molten means melted by extreme heat, transformed from solid to liquid by intense temperature. When rock becomes so hot that it turns into a flowing liquid, it becomes molten rock. When metal in a factory furnace gets hot enough to pour like water, it's molten metal.

The word specifically describes something that's normally solid but has been heated until it melts. You wouldn't say water is molten because water is naturally liquid at room temperature. But iron, which is normally hard and solid, becomes molten iron when heated to over 2,800 degrees Fahrenheit.

The most dramatic example of molten material is lava, which is molten rock that has erupted from a volcano. Deep beneath Earth's surface, the rock is so hot that it flows like thick honey. When it breaks through the surface, this lava can destroy everything in its path before eventually cooling back into solid rock.

Glassblowers work with molten glass, shaping it while it's still liquid and glowing. Blacksmiths once worked with molten metal to create tools. The word captures both the substance and its state: something that should be solid, now flowing and dangerous because of incredible heat.