Definition of running back in English:

running back

noun

American Football
  • An offensive player, typically a halfback, who specializes in carrying the ball.

    • ‘He also has the lateral agility and footwork to run with most tight ends and some running backs.’
    • ‘The offensive line and running backs are inconsistent, and the quarterbacks are green.’
    • ‘Both teams have to find a way to run the ball without their starting running back.’
    • ‘Look at all of the quality running backs, blockers, and wideouts.’
    • ‘The more carries a running back gets, the better chance he has of wearing down a defense.’