catflap.org Online Dictionary Query

  source route
       
           An electronic mail address which specifies the
          route the message should take as a sequence of hostnames.
          It is called a source route because the route is determined at
          the source of the message rather than at each stage as is now
          more common.  The most common kind of source route is a UUCP
          style bang path, "foo!bar!baz!fred'.  The RFC 822 syntax,
          "@foo:@bar:fred@baz", is seldom seen because most systems
          which understand RFC 822 also perform automatic routing based
          on the destination hostname.  A third, intermediate, form is
          sometimes seen: "fred%baz%bar@foo.com".
       
       

  source route /sˈɔːs ɹˈuːt/
  izvorni smjer