Run-off or runoff may refer to: Surface runoff, the flow of water, from rain, snowmelt, or other sources, over land Runoff model (reservoir), a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed Bleed (printing), printing that goes beyond the edge of the sheet after trimming Two-round system or runoff voting, a voting system used to elect a single winner, whereby only two candidates from the first round continue to the second round Instant-runo… (More on Runoff)