A crater is the mouth/ opening of the volcano. The molten magma is ejected through the vent of the volcano. The uppermost part of the vent or in other words the top opening of the vent is known as the crater. The crater is generally wider than the vent. When the lava/ejected material is sprayed all around the opening of the volcano, it dumps the lava around the volcano, thus forming a high circular embankment around the volcano. The basin-like part of the volcano is known as the crater of the volcano.