aftermarket

noun

1. the market for replacement parts, accessories, and equipment for the care or enhancement of the original product, especially an automobile, after its sale to the consumer: The company holds a large share in the automotive radio aftermarket.
2. any additional market created by a product after the primary market: Television is the perfect aftermarket for old movies.
3. Stock Exchange. secondary market.

adj.

1940, American English, of automobile parts, from after + market.