There is no acronym for “URL”. Instead URL is an acronym for Uniform Resource Locator and is a reference (an address) to a resource on the Internet.
An acronym is a word formed from the initial letter or letters of each of the successive parts or major parts of a compound term and is usually pronounced as a single word. Examples are: “laser" which originated as an acronym for "Light Amplification by Stimulated Emission of Radiation”, “ASCII” which stands for American Standard Code for Information Interchange and NATO, from North Atlantic Treaty Organization. The word acronym can also be used to refer to words formed by initialism, where the word is an abbreviation formed from initial letters but pronounced separately or distinctly, as with FBI and BBC.
