'aftermarket' originates from the combination of 'after' and 'market', where 'after' meant 'subsequent to' and 'market' referred to a place for buying and selling goods.

'aftermarket' was formed in modern English by combining 'after' and 'market' to describe a market that exists after the initial sale of a product.

Initially, it meant 'a market following the primary sale', and this meaning has largely remained the same in modern usage.