Home plate

From BR Bullpen

Home plate (abbreviated HP, as in the home plate umpire, who calls balls and strikes) is a five sided slab of rubber set into the infield to mark the position of home base. In a real sense, home plate is the center of action in any baseball game. The batter stands to one side of home plate in the batter's box, while the pitcher attempts to throw the ball through the strike zone, which is defined as a region directly above home plate. Offensive players score runs by circling the bases and returning to home.

The plate itself is defined by the rules to be [1]:

a five-sided slab of whitened rubber. It shall be a 17-inch square with two of the corners removed so that one edge is 17 inches long, two adjacent sides are 81/2 inches and the remaining two sides are 12 inches and set at an angle to make a point. It shall be set in the ground with the point at the intersection of the lines extending from home base to first base and to third base; with the 17-inch edge facing the pitcher’s plate, and the two 12-inch edges coinciding with the first and third base lines. The top edges of home base shall be beveled and the base shall be fixed in the ground level with the ground surface.