- a player of the team at bat who is on base or is trying to run from one base to another.
Origin of base runner
An Americanism dating back to 1865–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for base runner
As Roddy now saw it, he was again the base-runner, beset in front and rear.The White Mice
Richard Harding Davis
Team batting is the co-operation of batsman and base-runner.
The base-runner who must wait to be told what to do will always be too late.
At the bat, remember to keep a sharp eye on the base-runner, and when he signs he is going down, bunt or hit to advance him.The Young Pitcher
A steal is made when a base-runner gets from one base to another without the assistance of a base hit or an error.