Definition[]
URL is an acronym for Uniform Resource Locator. A URL (pronounced as "yoo aar el") indicates the protocol, name and location of a file on a computer network or a local computer.
How it works[]
A URL is different than an e-mail address. An e-mail address is location to which you would send a message file in order to reach a particular addressee. A URL, on the other hand, is a reference to a particular file. If somebody were to ask you for your URL, they would not be asking how to contact you; rather, they would likely be asking for the location and name of your World Wide Web home page file.
A URL is generally made up of three parts. The first part of a URL is the protocol specifier. This is the section of a URL up to and including the first set of slash marks. Examples are “http://” which indicates HyperText Transport Protocol, the standard for World Wide Web files; “ftp://” which indicates File Transfer Protocol, the standard for retrieving a file from a given host; or “file:///” which indicates a computer file of no particular protocol.
The second part of a URL is the domain at which the file resides. This may be an Internet domain such as “www.xyz.com” or it may be a disk drive designation on a local machine or network such as “c|/” or “d|/.” The end of a domain section of a URL may also include numbers indicating a network port, such as “www.xyz.com:8181/.”
The third part of a URL contains the path to a specific file. For example, the path “images/vacation/italy.html” indicates a file named “italy.html” located in the “vacation” subdirectory of the “images” directory of the server.
It should be noted that a URL will direct a user to a file with a particular protocol, location and name on a particular server, but it does not assure a user that the named file at a particular location is the same file that earlier was at the same location. From time to time any file designated by a URL may be altered or replaced by a different file with the same name. Thus, searching for a specific version of a file by using its URL can sometimes be like searching for the perfect wave — the same location, at the same beach, can have different waves from day to day.