URL nomenclature: Naming a certain part of an URL

I just can't get my head around a handy term to name the beginning part of an URI:

http://sub.domain.com/ ...

The official nomenclatu开发者_高级运维re of the various parts of my URI example is well known to me (protocol/scheme, host name made up of subdomain, domain name and tld ... you name it). But what would I call both, scheme and host name combined?

My best bet so far would be base URI.

What's yours?