If you get confused between URLs (Uniform Resource Locators) and URIs (Uniform Resource Identifiers), then simply think of a URL as a special type of URI used to point to resources on the WWW.
The term "URL" is now deprecated (a term meaning marked for removal in computing circles), and the term "URI" is now the accepted term in computer science. However with the rise of the internet "URL" has become entrenched within the English language and is used and understood widely among non computer scientists. It's not possible for any group of individuals to deprecate words (although plenty have tried...) so "URL" will probably long outlive its technical definition.
At the end of the day, I expect that if you should use the term "URL" when you really mean "URI" everybody will know what you mean!