money order/ purchase order / pay order

Dear teachers,

Would you tell me your opinion concerning the interpretation of the expression in bold in the following sentence?

You may get these books by money order.

order = a commercial document used to request someone to supply something in return for payment and providing specifications and quantities

money order = an order for the payment of a specified amount of money, usually issued and payable at a bank or post office

purchase order = a document containing a formal offer from an intending buyer to buy from a supplier the goods listed, in the quantities and at the approximate prices stated in the order

Could you tell me the difference between “money order” and “purchase order”?

In my native 1200 years “old” language we use for that purpose the term “pay order” which we hand in the cash counter.

Thanks for your efforts.

Regards,

V

A "money order" is issued, as you say, by a bank or post office. You present cash to them and they issue a piece of paper payable to a third party. This is used as an alternative to sending cash in the mail. Or when a person does not have a personal checking account. Or when the company to be paid does not accept personal checks. They want a guaranteed payment.

A "Purchase Order(PO)" is what a company issues to another company as the commitment to buy items or services. If I make widgets, your company may give me a PO for 500 widgets. I would then ship them to you and send you an invoice, which is a demand for payment. You would then have to pay me.