the.com/fullback

means A backfield player, lined up behind or beside the quarterback, whose job is to block, run short-yardage power plays, and occasionally catch a pass — the position built for collision rather than glory.

from Straightforward sports compounding: 'full' plus 'back,' describing where the player stood relative to other backs on the field. It comes out of 19th-century football and rugby formations, where backs were named by depth — fullback the deepest of them, positioned as the last line before the goal. Rugby still uses the term for a pure defensive last-man role; American football bent the job toward blocking and short bursts as offenses evolved, but the name stayed put even as the duties changed.