What is Crater ?
Crater is (noun) 1. a hole made by a bomb Over the winter, the bomb craters filled up with rainwater. 2. a round hole at the top of a volcano A group of scientists flew over the crater to monitor the activity of the volcano. 3. a round hole on the Moon or a planet, where a meteorite has hit it A map of the craters of the Moon.
source: Easier English, Student Dictionary Upper Intermediate Level