1. run by pass by while running
  2. run up pile up (debts or scores)
  3. run-up a substantial increase over a relatively short period of time
  4. runup a substantial increase over a relatively short period of time
  5. rainbow an arc of colored light in the sky caused by refraction of the sun's rays by rain
  6. runway a strip of level paved surface where planes can take off and land
  7. rugby a form of football played with an oval ball
  8. runny characteristic of a fluid
  9. runty (used especially of persons) of inferior size
  10. ruby a transparent piece of ruby that has been cut and polished and is valued as a precious gem
  11. runaway someone who flees from an uncongenial situation
  12. runabout an open automobile having a front seat and a rumble seat
  13. reunify unify again, as of a country
  14. runoff an election to resolve a vote that did not produce a winner
  15. run move fast by using one's feet
  16. roundup the activity of gathering livestock together so that they can be counted or branded or sold
  17. runner someone who travels on foot by running
  18. runnel a small stream
  19. run-on (verse) without a rhetorical pause between lines
  20. run on continue uninterrupted