Magma/ˈmæɡmə/ Definition 1 of 2Pro Tip 1/3Geological Term Used mainly in geology or earth sciences; may not be common in everyday conversation. Geologists study magma to understand volcanic activity. Pro Tip 2/3Internal Heat Implies intense heat as magma originates from deep within the Earth's mantle. The drill reached depths where the heat of the magma could be felt. Pro Tip 3/3Not Lava Yet Remember, magma refers to molten rock beneath the Earth's surface, not after it erupts. Magma turns into lava once it exits a volcano.