The Meadowlands track quickly became known as "the Big M."
http://www.thebigm.com/faq.asp
Q. Who was the first horse to win a pari-mutuel race at the Meadowlands?
A. Quick Baron was the first horse to win a pari-mutuel race at the Meadowlands on September 1, 1976.
19 December 1976, New York Times, pg. NJ4:
"Big M" Is Luring
Big Bettors
9 October 1985, Newsday (NY), pg. 113:
Young America at Big M Draws 13
Nicknames of Other Places • Big M (Meadowlands Race Track nickname) • (0) Comments • Sunday, April 10, 2005 • Permalink