1. (n.) A deep opening made by disruption; a breach in the earth or a rock; a void; a fissure\.

2. (n.) A void space; a gap or break, as in ranks of men.

abysm abyss aperture arroyo blank box canyon breach break broaching canyon cavity chap check chimney chink clearing cleavage cleft cleuch clough clove col coulee couloir crack cranny crater crevasse crevice cut cwm deep defile dell depth dig diggings dike disclosure ditch donga draw excavation fault fenestra fissure fistula flaw flume fontanel foramen fracture furrow gap gape gash gat gorge groove gulch gulf gully hiatus hole hollow incision inlet interval joint kloof lacuna laying open leak mine moat notch nullah opening opening up orifice outlet overlook oversight pass passage passageway pit pore preterition quarry ravine rent rift rime rupture scissure seam shaft skip slit slot space split stoma throwing open trench uncorking unstopping valley void wadi well workings yawn yawning abyss