'trade-in' originates from the English words 'trade' and 'in', where 'trade' meant 'exchange' and 'in' indicated 'inside or within'.

'trade-in' evolved from the practice of exchanging goods, particularly in the automotive industry, where older vehicles were traded in for newer models.

Initially, it meant 'to exchange goods', but over time it evolved into its current meaning of 'an item given as part of payment for something new'.