TRIPLE *U*

>> First of all (as you see in the diagram ) a URL is a type of URI.  If someone tells you that a URL is not a URI, it is wrong. But that it is doesn't mean all URIs are URLs. "All bees fly, but not everything that flies is a bee."
The part that makes a URI a URL is the insertion of the network location, For e.g. http://.
The URN is the globally unique part of the identification. It is a unique name.

Q: Which is the more proper term when referring to web addresses?
A: from what i have been researched on articles in the internet, It had say that URI is probably the better term to use.
WHY?
because if you use URI you will always be technically correct, and if you use URL you might not be corrected. So URI is a quite safe choice in terms of accuracy.