fullback vs. halfback

fullback

noun

Football.
  1. a running back who lines up behind the quarterback and is farthest from the line of scrimmage.
  2. the position played by this back.
  3. (in soccer, Rugby, field hockey) a player stationed near the defended goal to carry out chiefly defensive duties.

halfback

noun

  1. Football.
    1. one of two backs back who typically line up on each side of the fullback.
    2. the position played by such a back.
  2. (in soccer, Rugby, field hockey, etc.) a player stationed near the forward line to carry out chiefly offensive duties.