The Han River is the largest tributary of the Yangtze.
Tips
usage
Pairs with 干流 (main stem) or 主流 (mainstream). Used both literally for rivers and figuratively for ideas, movements, or factions - a 'minor branch' or 'side current' away from the dominant trend.
memory
支 'branch' + 流 'flow/current' - exact same metaphor as English 'tributary' (Latin tribuere, 'pay/contribute' as a branch contributes water to a main river).
