From Longman Dictionary of Contemporary Englishpostal orderˈpostal ˌorder noun [countable] British EnglishTCMMONEY an official document that you buy in a post office and send to someone so that they can then exchange it for money SYN money order American English
Examples from the Corpus
postal order• If you paid by postal order, take the counterfoils to the post office for a refund.• Send the coupon, and cheque or postal order if applicable to, .• You should print your name and address on the back of the cheque or postal order.• Please return it at once, or when sending the postal order.• Coins Any uncrossed postal order which does not state to whom it is to be paid.From Longman Business Dictionarypostal orderˈpostal ˌorder written abbreviation PO noun [countable] British English a document bought at a post office which can be sent through the post and exchanged for moneySend a cheque or postal order for £13.99 to the address below. → compare money order 