tributary

nouns

a branch that flows into the main stream
antonym

adjectives

(of a stream) flowing into a larger stream
is similar to
being of second rank or importance or value; not direct or immediate
"the stone will be hauled to a secondary crusher"; "a secondary source"; "a secondary issue"; "secondary streams"
paying tribute
"a tributary colony"
is similar to
caused by law or conscience to follow a certain course
"felt obligated to repay the kindness"; "was obligated to pay off the student loan"
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"