1. Customers other than those to whom a product was originally offered. For example, tools designed and priced for professionals may also be bought by serious hobbyists.
2. Financial market where previously issued securities (such bonds, notes, shares) and financial instruments (such as bills of exchange and certificates of deposit) are bought and sold. All commodity and stock exchanges, and over-the-counter markets, serve as secondary markets which (by providing an avenue for resale) help in reducing the risk of investment and in maintaining liquidity in the financial system.
3. Alternative term for aftermarket.