bawl definition: To bawl is defined as to cry or wail loudly. (verb) An example of bawl is to sob loudly upon hearing bad news. ...
Consider these examples. When accepted by a vendor every PO becomes a contract, but not every contract is a PO. Some (but not all!) people view POs as a kind of one-time contract. Purchase Orders may cross-reference the terms of a negotiated contract. It's a common misconception that the level of detail in a PO is less than that of a contract.
With a Purchase Agreement, normally what you find is language that says that as long as the purchase order issued complies with the terms of the Purchase Agreement it is issued under, that order is binding and enforceable. The difference between the two has nothing to do with the time period involved. A Blanket Purchase Order may be for long period and a purchase agreement may be for a very short period. The difference has nothing to do with the volume involved.