Avenue, Bank, Bevel, Carousel, Cascade, Cataract, Channel, Chimney, Collapse, Comedown, Crash, Debacle, Declension, Declination, Deposit, Descending, Descent, Door, Down, Downfall, Downgrade, Downpour, Downturn, Drop, Dropping, Egress, Escape, Estuary, Exhaust, Exit, Fall, Falling, Falls, Force, Grade, Gradient, Gravitation, Guide, Gutter, Harness, Hillside, Inclination, Incline, Lode, Loophole, Matrix, Opening, Out, Outcome, Outfall, Outgo, Outlet, Pack, Parachute, Pitch, Plummeting, Pore, Port, Pounce, Ramp, Rapid, Rapids, Riff, Riffle, Ripple, Roundabout, Runway, Scarp, Seesaw, Shaft, Shoot, Side, Slide, Slope, Sluice, Spout, Stock, Stoop, Swing, Swoop, Tap, Trough, Umbrella, Vein, Vent, Waterfall, Weir, Whip, Whirligig