1. A funnel-shaped cavity on the sea floor produced by escaping gas; a pockmark. 2. A funnel-shaped cavity at the top of a borehole resulting from loose material falling into the borehole, especially resulting from the detonation of a shot in the borehole. 3. The result of an impact such as a meteor crater, sometimes called an astrobleme. 4. To crash (q.v.).