By Roger Weber
One wouldn't be alone arguing that the most recognizable symbol of a baseball field is home plate. Recently Qualcomm
Stadium and Comerica Park have even shaped their infield
dirt in the shape of the plate. The famous hard plastic surface is five sided but not an equilateral pentagon, the front side
being longer than the others. The front side is 17 inches across. The bottom two sides that form a point where the catcher
sits are 12 inches and the remaining two sides are each 8.5 inches. The front
edge of the plate is the measurer of the sides of the strike zone, is generally (although not specified in the rule book as
such) used as the determiner of whether a player checked his swing or not, and has been used as a calibrating machine to measure
the legality of the amount of pine tar on a bat – just ask George Brett.
Home plate is also a symbolic part of the field. Umpires famously brush off home plate during pauses, sometimes using
that action as an excuse to have a break in the action. Home plates have been carried by helicopter during numerous old-to-new
park ceremonies.
But home plate wasn't always a pentagon, and the origins of the term are debatable. But 1900 was the first year a pentagonal
plate was used.