Definitions of runner:

• noun:   fish of western Atlantic: Cape Cod to Brazil
• noun:   device consisting of the parts on which something can slide along
• noun:   a long narrow carpet
• noun:   a person who is employed to deliver messages or documents

  Example: "He sent a runner over with the contract"

• noun:   someone who travels on foot by running
• noun:   a trained athlete who competes in foot races
• noun:   a baseball player on the team at bat who is on base (or attempting to reach a base)
• noun:   someone who imports or exports without paying duties
• noun:   a horizontal branch from the base of plant that produces new plants from buds at its tips
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #13169)