http://jptvwdeyknkv6oiwjtr2kxzehfnmcujl7rf7vytaikmwlvze773uiyyd.onion?page=9142487784117373961519
If we decide to define it as
"a name that connects you to a specific Tor client," then foo.xyz.onion and
bar.xyz.onion are the same onion service. They are both going to the Tor client
serving xyz.onion. Tor doesn't handle subdomains like that. If you go through the process of
hosting two websites at the same onion domain, you'll realize you have to do it
at the level of the webserver.