A ruler or state that pays tribute, or a stated sum, to a conquering power, for the purpose of securing peace and protection, or as an acknowledgment of submission, or for the purchase of security
A tributary is a stream or river that flows into a larger one. the Napo river, a tributary of the Amazon. tributaries a stream or river that flows into a larger river
means any stream that flows into a larger stream, or into a lake or reservoir This includes a tributary to a tributary Tributaries to a lake are considered to be tributaries to the outlet stream from the lake unless stated differently in site-specific regulations
tending to bring about; being partly responsible for; "working conditions are not conducive to productivity"; "the seaport was a contributing factor in the growth of the city"; "a contributory factor"