Difference between URL and URI

“…a URL is a type of URI that identifies a resource via a representation of its primary access mechanism (e.g., its network “location”), rather than by some other attributes it may have. Thus as we noted, “http:” is a URI scheme. An http URI is a URL. The phrase “URL scheme” is now used infrequently, usually to refer to some subclass of URI schemes…”
URI stands for Universal Resource Identifier and URL stands for Universal Resource Locator. Often times people use the terms interchangably, which is not entirely correct. A URL is a subset of the URI popular protocols. These are protocols (http://, ftp://, mailto:). Therefore all URLs are URIs. The term URL is deprecated and the more correct term URI is used in technical documentation. All URIs are means to access a resource on the Internet and are a a technical short hand used to link to the resource. URIs always designate a method to access the resource and designate the specific resource to be accessed.” >

A URI is an identifier for some resource, but a URL gives you specific information as to obtain that resource. A URI is a URL and as one commenter pointed out, it is now considered incorrect to use URL when describing applications. Generally, if the URL describes both the location and name of a resource, the term to use is URI. Since this is generally the case most of us encounter everyday, URI is the correct term.