The 'L' of N.F.L. stands for LEAGUE, which is a 6 letter word. The National Football LEAGUE (N.F.L.) is the highest level of professional American football in the United States. It is made up of 32 teams divided into two conferences, the National Football Conference (NFC) and the American Football Conference (AFC). The N.F.L. is one of the four major professional sports leagues in North America and is the most popular sports LEAGUE in the United States.