chasm

English Thesaurus

1. a deep opening in the earth's surface (noun.object)

hypernym	:	gap, opening,
definition	:	an open or empty space in or between things (noun.object)

hyponym	:	abysm, abyss,
definition	:	a bottomless gulf or pit; any unfathomable (or apparently unfathomable) cavity or chasm or void extending below (often used figuratively) (noun.object)

hyponym	:	gulf,
definition	:	a deep wide chasm (noun.object)