Hash marks

Hash marks are short lines, running perpendicular to sidelines or sideboards, used to mark locations, primarily in sports.

Usage in ice hockey
In ice hockey, the hash marks are two pairs of parallel lines on either side of the face-off circles in both ends of the rink. Players must remain on their team's side of the hash mark nearest their own goal during a face-off until the puck hits the ice.

Usage in gridiron football
In American football and Canadian football, the hash marks are two rows of lines near the middle of the field that are parallel to the side lines. These small lines (about 1 yard long) are used to mark each of the 5-yard lines, which go from sideline to sideline. All plays start with the ball on or between the hash marks. That is, if the ball is downed in between a hash mark and the nearest sideline, it must be reset on the hash mark for the next play. Prior to the adoption of hash marks (which were first utilized at the first NFL playoff game in 1932), all plays began where the ball was declared dead, including extra point attempts.

In most forms of professional football, including the National Football League, Canadian Football League, and most forms of indoor football, the hash marks are in line with the goal posts, both being 18 feet 6 inches (in the NFL and CFL) apart. Both high school football and college football have hash marks significantly wider than the goal posts. The college football standard is 40 feet apart; the high school standard is one-third of the width of the field (53 feet, 4 inches).