URL is Internet jargon ("Uniform Resource Locator"). In a non-technical sense it means "internet address", something like " http://www.google.com/path/page.html". It's like a phone number: only if it's completely correct you arrive at the desired location - if a single character is wrong, you end up nowhere (with an error message).
The parts of the example:
Many parts of the URL are optional and may be dropped in certain situations. For example current browsers understand that users want webpages, so they will automatically add the protocol "http" if it is not given.
- e. g. http://www.google.com/path/page.html
- http -- the protocol (there are many other protocols)
- www -- the default "sublevel domain" for webpages (optional)
- google -- the domain part, but "domain" usually includes the top-level domain
- com -- the toplevel domain, most are denoting countries (fr = France)
- path -- "directory" information
- page.html -- file name or something similar