protocol- "the official procedure or system of rules governing affairs of state or diplomatic occasions."
http means- HyperText Transfer Protocol
HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands.
Uniform Resource Locator, previously Universal Resource Locator – usually pronounced by sounding out each letter. URL – is the unique address for a file that is accessible on the Internet. A common way to get to a Web site is to enter the URL of its home page file in your Web browser's address line.