half ‧ back /ˈhɑːfbæk $ ˈhæf-/ BrE AmE noun [countable]
1 . a player in a game of football, ↑ rugby , ↑ hockey etc who plays in the middle part of the field
2 . a player in American football who, at the start of play, is behind the front line of players and next to the ↑ fullback