The crater of a volcano.

A bowl- or funnel-shaped hollow at the summit or on the side of a volcano, from which eruption takes place; the mouth of a volcano.

a rimless, roughly circular, and often steep-sided crater or small caldera formed by the collapse of the ground on or near a volcano.

A deep cauldron-like cavity on the summit of an extinct volcano.

A broad, low-rimmed, usually lake-filled volcanic crater of the kind exemplified by the Eifel Maars, formed by an explosion with little lava at a…