yes it is in the rules of baseball.
Hat
The player, himself, decides what hat will be worn.
slowbucks
to keep the the sun out of the players face so that they can focus
Cap Anson Mordecai Brown
Button-Up Jersey, Baseball Pants, Long Socks, Cleats, Baseball Cap, Etc.
New Era Cap Company is the official baseball cap that is worn by all MLB teams. The company was founded in 1920 by a German immigrant named Ehrhardt Koch.
The person who answered before said 'baseball cap' but baseball is not a British game. It is a Cricket Cap. Cricket is a game played in the UK.
The significance of the baggy green cap is that it symbolizes the Australian pride. The cap itself is a cricket cap and it is considered to be the most famous cricket cap.
A bathing cap is a silicone, latex or lycra cap which is worn on the head by swimmers.
The cap that was worn by the common soldiers during the American Revolution was called a tricorn. The shako cap can be traced back to War of 1812.