| cut(noun, depression, hollow, ditch, scrape) |
| dike(noun, depression, drain, ditch, channel) |
| excavation(noun, drain, dip, ditch, bottom) |
| valley(noun, dip, hollow, bottom, gorge) |
| conduit(noun, line, course, drain, means) |
| tub(noun, tray) |
| basin(noun, gorge, vale) |
| crib(noun, depression, rack, gutter, manger) |
| gully(noun, depression, ditch, channel, pit) |
| mine(noun, channel, pit, trench, quarry) |
| aqueduct(noun, course, means, race, flow) |
| concavity |
| dent(noun, depression, hollow, scrape, indentation) |
| duct(noun, line, depression, course, drain) |
| flute(noun, groove) |
| fosse(noun, furrow) |
| ravine(noun, groove, furrow) |
| slump(noun, decline, failure, depression, recession) |
| dale(noun, dip, bottom, gorge, valley) |
| gouge |