the.com/quarterback

means The offensive player who takes the snap and directs the play — throwing, handing off, or running — making him the on-field leader of a football team's attack.

from Straightforward position-naming from American football's early days: the backfield players were lined up at different depths behind the line, called 'quarter back,' 'half back,' and 'full back' depending on how far back they stood. The quarterback started as the man positioned closest to the line, a touch behind it — a literal quarter of the way back — not originally the glamour job it became once forward passing turned him into the team's on-field brain.