What is the proper term for (example) hostname.tld:433 (hostname:portnumber)?

It is not just hostname, and it is not really a URL either :) same goes for etc.


5 Answers 5


IP address and port pair is called, Socket Address

Pair of socket addresses (, may also be called 4-tuple or 5-tuple if the protocol is specified as well (, UDP)

  • 2
    This is more true in the programming/systems world and not always as relevant in networking. In networking the IP address and port/protocol are generally distinct and specific values, and not used as a single value.
    – YLearn
    Commented Jun 17, 2014 at 15:45

I've been writing a lot of network code over the years, and the word "endpoint" seems to be the term for "a specific port on a specific IP address".

Have a look at the Boost documentation as well as the Microsoft documentation:



  • See stackoverflow.com/questions/47488910/… -- an endpoint is a more general term than a socket; there are are non-TCP endpoints.
    – David J.
    Commented Jun 26, 2021 at 4:01
  • Note that "endpoint" has a different meaning in web services. In web services, an endpoint is a complete URL. Commented Feb 3 at 1:59

According to the DOM/Web API it is simply host.

The host property of the URL interface is [...] the hostname, and then, if the port of the URL is nonempty, a ':', and the port of the URL.

You can see this in a browser console:

url = new URL('http://example:8080/path')
url.hostname  // "example"
url.host      // "example:8080"

If your use case covers the optional 'authentication' section, then this would be called an "authority".

[A URI] comprises:


  • An authority part, comprising:

    • An optional authentication section of a user name and password, separated by a colon, followed by an at symbol (@)
    • A "host", consisting of either a registered name (including but not limited to a hostname), or an IP address. IPv4 addresses must be in dot-decimal notation, and IPv6 addresses must be enclosed in brackets ([ ]).
    • An optional port number, separated from the hostname by a colon



It is formalized in RFC 3986 - Uniform Resource Identifier (URI): Generic Syntax

The authority component is preceded by a double slash ("//") and is terminated by the next slash ("/"), question mark ("?"), or number sign ("#") character, or by the end of the URI.

authority   = [ userinfo "@" ] host [ ":" port ]

I would call generically describe (IPAddress, Port) as an IP Service.

If used in DNS context, then look up DNSSRV records.

If used in Socket context, then it is a Socket Address.

Another context could be use in a regular expression used in filtering Flows.

Or use in router or firewall in an access-list.

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