Rill (noun)

A small stream or narrow channel cut into soil or rock by the erosive action of flowing water.

Origin:

From old english "rill" meaning "a small stream".

Examples:

1. The rainwater formed rills on the hillside.
2. The rill flowed into a larger stream.
3. The rill was a source of water for the animals.
4. The rill provided irrigation for the fields.
5. The rill was a sign of water erosion in the area.