From Longman Business Dictionaryexchange of contractsexˌchange of ˈcontracts noun (plural exchanges of contracts) [countable usually singular] PROPERTY when property is being bought and sold, the moment when the buyer signs the contract of sale and sends it to the seller, who also signs it, making the sale effectiveExchange of contracts is the vital moment of agreement, after which it is very difficult to withdraw without stiff financial penalties.
