Definitions for aftermarketˈæf tərˌmɑr kɪt, ˈɑf-
Random House Webster's College Dictionary
af•ter•mar•ketˈæf tərˌmɑr kɪt, ˈɑf-(n.)
the market for parts, accessories, etc., for maintaining the original product.
Origin of aftermarket:
The market for goods and services surrounding capital purchases of equipment and of software.
The industry that serves that market, eg, in automobiles, computers.
Trading activity in a security immediately following its initial offering to the public.