In baseball, it's the area enclosed by the 3 bases & home plate
Unlike the other bases the home plate is a flat slab of rubber, pentagonal 
in ... a base to the next is made of mud or dirt, and the diamond is enclosed by 
base ... is 18 ft in diameter and a white rubber slab rectangular in shape of 5 ft  3 
ft... [DOC] [TLE] Associations to the word Infield - Word Associations Network [PAR] The area inside a racetrack or running track.