More specifically...
The M1A is a copyrighted and registered trade name of Springfield Armory, Incorporated, out of Geneseo, Illinois. It's what they call their own semi-auto version of the U.S. Rifle, Caliber 7.62mm, M14. The term M1A, since it is copyrighted, cannot be used by other manufacturers of semi-auto M14 copies, although it's commonly used to describe them, much like Xerox is used to describe copiers made by other manufacturers. Other semi-auto copies of the USGI M14 rifle include the Armscorp M14NM and LRB M14SA rifles.