tributary
A stream or river called that flows into a larger stream or river is called a tributary.
A tributary.
A Tributary
The stream is a tributary of the river.
River, stream, waterway, brook, canal, or watercourse
Streams run into larger rivers.
Streams run into larger rivers.
It's called a tributary.
Tributary
A small freshwater river or stream flowing into a larger river is called a tributary or feeder river. A tributary is a stream or river that flows into a mainstem (or parent) river or a lake. For example, a tributary can be a creek that flows into a river. Or it can be a small river that flows into a larger river. A tributary does not flow directly into a sea or ocean. Some large rivers can have up to 100 tributaries. The spot where the smaller and larger river meet is called a "confluence". In contrast, a body of water that branches off and flows away from the main river is called a distributary.
stream, creek or either a lake or a ocean
They join together- it is called a tributary xx