From Longman Business Dictionaryfirm saleˌfirm ˈsaleCOMMERCE1[countable, uncountable] when a shop buys a quantity of goods from a supplier, and cannot return any goods it does not sellSpecialist booksellers usually have a minimum order and offer only firm sales.2[countable] an agreement to buy something, but for which no payment has actually been receivedAre you sure this is a firm sale? → sale
