The strip is called "the rubber". I am an umpire and this is what i know it as. I am not sure if it is the official name, but if you say the term in context to the strip on the mound, anyone who knows Baseball will know what you mean. It is unlikely that the term will be confused with anything else as everyone from announcers to umpire use it.
to legally play only one person can be on the pitchers mound while the game is in play
The diameter of an MLB pitcher's mound is 18 feet.
It is called a foul
Measure from the front edge of the pitching rubber to the back tip of home plate.
More than likely a pitcher's mound is removed by smoothing the dirt out with a bulldozer.
The mound allows pitchers a much better chance of pitching within the strike zone.