Definition: URL is an acronym for Uniform Resource Locator and is a reference (an address) to a resource on the Internet. A URL has two main components: 1  Protocol identifier: For the URL http://example.com, the protocol identifier is http. 2  Resource name: For the URL http://example.com, the resource name is example.com. URL has two main components: 1  Protocol identifier: For the URL http://example.com, the protocol identifier is http. 2  Resource name: For the URL http://example.com, the resource name is example.com.