—n. 1. a stream that flows to a larger stream or other body of water.
2. a person or nation that pays tribute in acknowledgment of subjugation or the like.
—adj. 1. (of a stream) flowing into a larger stream or other body of water.
2. furnishing subsidiary aid; contributory.
3. paying or required to pay tribute.
4. paid as tribute.
5. subject; subordinate: a tributary nation.