In finance terms the difference between aftermarket and aaa

is that aftermarket is trading activity in a security immediately following its initial offering to the public while aaa is the highest credit rating given by debt analysis agencies such as Standard & Poor's, Moody's, and A.M. Best.

As nouns the difference between aftermarket and aaa

is that aftermarket is the market for goods and services surrounding capital purchases of equipment and of software while aaa is initialism of lang=en.

As a symbol AAA is

the highest level of minor league baseball, often used by extension in other sports to indicate the highest level of minor league play in that sport as well.

As an initialism AAA is

Abdominal aortic aneurysm

As a proper noun Aaa is

alaska.