Major, important.
Of or relating to an artery.
A through road.
Serious, high-level; significant
Of or pertaining to a major sports league; belonging to the professional level of a sport, such as US baseball.
Analogous in importance to a major league sports team.
An association of sports teams which plays at the highest skill level of its sport, especially Major League Baseball.
The highest level of competition in a field of endeavor.