A gully is a narrow channel or small valley carved into the ground by running water. When rain falls on a hillside or slope, it doesn't always soak into the soil. Instead, the water runs downhill, and over time, it can wear away the earth and rock, creating a ditch or trench. These erosion channels are called gullies.

You might see gullies in farmland where heavy rains have cut deep grooves into fields, or on mountainsides where streams have carved V-shaped trenches. Gullies start small, but they can grow wider and deeper with each storm. Some gullies are shallow enough to step over, while others are so deep you could hide inside them.

In dry regions, gullies might stay empty most of the year but suddenly fill with rushing water during rare rainstorms. Farmers and landowners often work to prevent gullies from forming because they can damage crops and make land harder to use.

Less commonly, gully can refer to a large knife or to a fielding position in cricket, though you're most likely to encounter the erosion meaning.