Definitions for fullbackˈfʊlˌbæk
Random House Webster's College Dictionary
(in football) a running back who lines up behind the quarterback and is farthest from the line of scrimmage.
the position played by this back.
(in soccer, Rugby, and field hockey) a player stationed near the defended goal to carry out chiefly defensive duties.
Origin of fullback:
(football) the running back who plays the fullback position on the offensive team
(American football) the position of a back on a football team
play the fullback
An offensive back whose primary jobs are to block in advance of the halfback on running plays and for the quarterback on passing plays.
A defensive player who assists the goalie in preventing the opposing team from scoring.