runoff

noun4

1. •
   A second or further round of a competition, after other competitors (often all but the last two) have been eliminated.
2. •
   A second or further round of an indecisive election, after other candidates (often all but the last two) have been eliminated.

   • There will now be a runoff as neither front runner received more than 50% of the vote.
3. •
   That portion of precipitation or irrigation on an area which does not infiltrate or evaporate, but instead is discharged from the area.
4. •
   Dissolved chemicals, etc, included in such water.

   • The runoff of nitrates is poisoning the lake.