The kicking team (determined by the winner of the coin toss) kicks the ball from the free kick line (the 35-yard line in pro football, the 40-yard line in high school and college). This is the kickoff, the start of the game.
when a player kicks a ball from a tee at his own 30-yard line (35 in college) to the opposing team, whose player tries to advance it the other way; used to start the game, the second half and overtime, and to restart play after each score.
A kick which starts the game and also the second half. The team that kicks off to start the game receives the kickoff to start the second half. If the game goes into overtime a coin toss is used to determine who kicks off in the overtime.