Cataract Canyon - a tributary of the Grand Canyon

Grand Canyon - the enormous gorge of the Colorado River in northern Arizona

flume, gulch - a narrow gorge with a stream running through it

Olduvai Gorge - a gorge in northeastern Tanzania where anthropologists have found some of the earliest human remains

ravine - a deep narrow steep-sided valley (especially one formed by running water)

mountain pass, notch, pass - the location in a range of mountains of a geological formation that is lower than the surrounding peaks; "we got through the pass before it started to snow"

passageway, passage - a path or channel or duct through or along which something may pass; "the nasal passages"

muscle system, muscular structure, musculature - the muscular system of an organism

alimentary canal, alimentary tract, digestive tract, digestive tube, gastrointestinal tract, GI tract - tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

epicardia - the short part of the esophagus extending downward from the diaphragm to the stomach

cardiac sphincter - the valve between the distal end of the esophagus and the stomach; the physiological sphincter at the esophagogastric junction

eat - eat a meal; take a meal; "We did not eat until 10 P.M. because there were so many phone calls"; "I didn't eat yet, so I gladly accept your invitation"