Topic summary
Backfield

Extracted from the Wikipedia article Offensive backfield.
Play in the backfield
Players who are positioned behind the line of scrimmage, on the offensive side, are denominated as "offensive backfield." Those players are usually ball receivers, so they have the word "back" appended to their position: i.e., running back, full back, half back and quarterback. However, because the word "backfield" is a place, sometimes receivers can be appended to the grouping.