John Tomlinson Brush was an owner of the baseball New York Giants who died in 1913. In 1911, the Polo Grounds was then called "Brush Stadium."
8 April 2006, New York Post, pg. 23, col. 1:
Yankee Stadium was the first ballpark to be called a "Stadium" rather than a "Field," a "Park" or a "Grounds."
Yankee Stadium is the home stadium of the New York Yankees, a major league baseball team. Located at East 161st Street
and River Avenue in The Bronx, New York City, it originally
opened on April 18, 1923 and reopened on April 15, 1976 after an
extensive three year renovation. The first night game was played on May 28, 1946.
Yankee Stadium is often referred to as "The House that Ruth Built", but it is usually referred to as "The Stadium". It was the first baseball park to be labeled a "Stadium" rather than a "Field," a "Park," or a "Grounds," and it conformed to the usage of the term in ancient Greece, where a stadium was a foot-race arena. Yankee Stadium's field was initially surrounded by a (misshapen) quarter-mile running track, which effectively also served as an early "warning track" for fielders, a feature now standard in all major league ballparks.
(See "Brush Stadium" -- ed.)
17 April 1912, Los Angeles Times, pg. III2:
Twelve thousand Portland fans today dedicated the greatest baseball stadium on the Pacific Slope and incidentally they saw San Francisco win from the champions, 2 to 1.