main vent - this is the channel through which magma travels to reach the Earth's surface. secondary vent - some magma may escape through the side of the volcano, particularly if the main vent becomes blocked. crater - this is found at the top of the volcano, where the magma erupts from.
There are multiple holes, or vents, from which magma can exit from in a volcano. The biggest one, usually at the top, which most of the magma comes out of, is called the "main vent".
