Runner can mean several different things:

1. A person who runs, whether for exercise, competition, or sport. Marathon runners train for months to build the endurance needed to complete 26.2 miles. Some runners sprint short distances as fast as they can, while others prefer long, steady runs through parks or neighborhoods. Track and field has different types of runners: sprinters who explode with speed for 100 meters, middle-distance runners who balance speed and stamina, and distance runners who sustain their pace for miles.
2. A long, narrow rug or strip of carpet, typically placed in hallways or along tables. A table runner might protect the wood surface during meals or add decoration to a dining room. Hall runners cushion footsteps and add warmth to long corridors.
3. Someone who delivers messages, packages, or documents. Before phones and email, offices employed runners to carry messages between buildings. Banks still use runners to transport checks and documents between branches. A runner in a restaurant might bring food from the kitchen to tables when the restaurant is busy.

The word also appears in phrases like baserunner in baseball (a player running between bases).