a small river or stream
A tributary or affluent is a stream or river that flows into a main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the Main stem river serve...
tributaries are created by water eroding rocks to make a stream or river
They are typed and printed onto newspapers. XD
when one stream meets another and they merge together, the smaller stream is known as a tributary.