part exchange
noun /ˌpɑːt ɪksˈtʃeɪndʒ/
/ˌpɑːrt ɪksˈtʃeɪndʒ/
[uncountable] (British English)- a way of buying something, such as a car, in which you give your old one as part of the payment for a more expensive one
- in part exchange We'll take your old car in part exchange.