tributary(n = noun.object) affluent, confluent, feeder - a branch that flows into the main stream;
is a kind of branch
Antonym: distributary

1.  tributary(s = adj.all) - (of a stream) flowing into a larger stream;

2.  tributary(s = adj.all) - paying tribute; "a tributary colony"

3.  tributary(s = adj.all) conducive, contributing, contributive, contributory - 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"

1.  Paying tribute to another, either from compulsion, as an acknowledgment of submission, or to secure protection, or for the purpose of purchasing peace. [1913 Webster]
"[Julius] unto Rome made them tributary." [1913 Webster]

2.  Hence, subject; subordinate; inferior. [1913 Webster]
"He to grace his tributary gods." [1913 Webster]

3.  Paid in tribute. Shak. [1913 Webster]

4.  Yielding supplies of any kind; serving to form or make up, a greater object of the same kind, as a part, branch, etc.; contributing; as, the Ohio has many tributary streams, and is itself tributary to the Mississippi. [1913 Webster]

1.  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. [1913 Webster]

2.  A stream or river flowing into a larger river or into a lake; an affluent. [1913 Webster]

tributary, n. & adj.
--n. (pl. -ies)
1 a river or stream flowing into a larger river or lake.
2 hist. a person or State paying or subject to tribute.
--adj.
1 (of a river etc.) that is a tributary.
2 hist. a paying tribute. b serving as tribute.

Derivative:
tributarily adv. tributariness n.

Etymology:
ME f. L tributarius (as TRIBUTE)

N  giving, bestowal, bestowment, donation, presentation, presentment, accordance, concession, delivery, consignment, dispensation, communication, endowment, investment, investiture, award, almsgiving, charity, liberality, generosity, gift, donation, present, cadeau, fairing, free gift, boon, favor, benefaction, grant, offering, oblation, sacrifice, immolation, lagniappe, pilon, grace, act of grace, bonus, allowance, contribution, subscription, subsidy, tribute, subvention, bequest, legacy, devise, will, dotation, dot, appanage, voluntary settlement, voluntary conveyance, amortization, alms, largess, bounty, dole, sportule, donative, help, oblation, offertory, honorarium, gratuity, Peter pence, sportula, Christmas box, Easter offering, vail, douceur, drink money, pourboire, trinkgeld, bakshish, fee, consideration, bribe, bait, ground bait, peace offering, handsel, boodle, graft, grease, blat, giver, grantor, donor, feoffer, settlor, giving, given, allowed, allowable, concessional, communicable, charitable, eleemosynary, sportulary, tributary, gratis, donative, auctor pretiosa facit, ex dono, res est ingeniosa dare.

N  river, running water, jet, spirt, spurt, squirt, spout, spray, splash, rush, gush, jet d'eau, sluice, water spout, water fall, cascade, force, foss, lin, linn, ghyll, Niagara, cataract, rapids, white water, catadupe, cataclysm, debacle, inundation, deluge, chute, washout, rain, rainfall, serein, shower, scud, downpour, driving rain, drenching rain, cloudburst, hyetology, hyetography, predominance of Aquarius, reign of St. Swithin, mizzle, drizzle, stillicidum, plash, dropping, falling weather, northeaster, hurricane, typhoon, stream, course, flux, flow, profluence, effluence, defluxion, flowing, current, tide, race, coulee, spring, artesian well, fount, fountain, rill, rivulet, gill, gullet, rillet, streamlet, brooklet, branch, runnel, sike, burn, beck, creek, brook, bayou, stream, river, reach, tributary, geyser, spout, waterspout, body of water, torrent, rapids, flush, flood, swash, spring tide, high tide, full tide, bore, tidal bore, eagre, hygre, fresh, freshet, indraught, reflux, undercurrent, eddy, vortex, gurge, whirlpool, Maelstrom, regurgitation, overflow, confluence, corrivation, wave, billow, surge, swell, ripple, anerythmon gelasma, beach comber, riffle, rollers, ground swell, surf, breakers, white horses, whitecaps, rough sea, heavy sea, high seas, cross sea, long sea, short sea, chopping sea, hydrodynamics, hydraulics, hydraulicostatics, rain gauge, flowmeter, pegology, irrigation, pump, watering pot, watering cart, hydrant, syringe, garden hose, lawn spray, bhisti, mussuk, fluent, diffluent, profluent, affluent, tidal, flowing, meandering, meandry, meandrous, fluvial, fluviatile, streamy, showery, rainy, pluvial, stillicidous, stillatitious, for men may come and men may go but I go on foreve, that old man river, he just keeps rolling along.