Postpaid meaning is different between document and dictionary

[fenglish]

Hi,

Below is from a technical document about "Payment Type".

Payment Type:
Select Postpaid if the customer pays after using the service.
Select Prepaid if the customer pays before using the service.

From the above type definition, we know the Postpaid means the payment will be pay after using the service.
But from dictionary, I found a different meaning for "Postpaid".

Oxford: that you can send free because the charge has already been paid.
--> a post-paid envelop.
Longman: costing nothing to send because the amount has already been paid.

In the definition of Oxford and Longmand, the postpaid indicates the payment have already been paid before. But from the document and my understanding, the postpaid should be indicate that the payment still not be pay.

Please help to explain if something wrong?
Thanks.

 

[fenglish]

I think it is my understanding problem, the first "postpaid" is not the same as "post-piad" from dictionary. Sorry for posting a wrong post.

 

[Tarheel]

There is nothing wrong. The document clearly defines the terms used, and the definitions are logical. Longman's definition is not wrong, but you can't expect it to fit every situation.

 

[emsr2d2]

In the UK, an envelope on which the postage cost has already been paid so that someone can then put something in it and send it for free, is called a "pre-paid envelope".

In your first example, using "Post paid", the word "post" means "after".
In your second example, using "post-paid", the word "post" means "postage charge".