'halfback' definitions:

Definition of 'halfback'

(from WordNet)
noun
(football) the running back who plays the offensive halfback position
noun
(American football) the position of a back on a football team

Definition of 'halfback'

From: GCIDE
  • halfback \halfback\ n. (Football) A person who plays the position of halfback[2] on a football team.
  • Syn: running back. [WordNet 1.5]
  • 2. The position of either of two players on a football team who typically begins each play behind the line and on either side of the quarterback. [WordNet 1.5 +PJC]