"Fourth and goal" is a term used in American and Canadian football when the team in control of the ball is on its 4th down and is fewer than 10 yards from the opposing team's goal line. Crossing the other team's goal line results in a touchdown.
Both American and Canadian football use a system in which each team has four opportunities, or "downs," to advance 10 yards down the field. If the team fails to do so, the ball changes hands to the other team. The fourth down is the final down and is the last chance for the team to complete its advance of 10 yards or score before its possession of the ball is over.