Actually, its NOT the same thing, dummy. Once again, try taking your own advice and googling an answer before you respond back. A URL requires a defined protocol to be valid.
www.abc.com is a domain,
http://www.abc.com is a URL. So are
https://www.abc.com,
ftp://www.abc.com, ftps:// etc. You get the point.
The two are not interchangeable.