[1] [DFN[[RUBYB[完全修飾ドメイン名]@en[Fully Qualified Domain Names]]]] ([[FQDN]]) は、
[[TLD]] を含む、省略されていない[[ドメイン名]]です。

[FIG(quote)[
[FIGCAPTION[
[2] ([TIME[2014-11-01 05:54:38 +09:00]] 版)
<https://cabforum.org/wp-content/uploads/BRv1.2.3.pdf#page=10>
]FIGCAPTION]

> Fully-Qualified Domain Name: A Domain Name that includes the labels of all superior nodes in the Internet
> Domain Name System. 

]FIG]

[3] [[ワイルドカード]]を含むものを[[ワイルドカードFQDN]]と言うことがあります。

;; [[ワイルドカードFQDN]]が [[FQDN]] の一種なのか否かは明らかではありません。

[4] [CODE[[[.]]]] ([[末尾の点]] = [[根ドメイン]]) で終わる[[ドメイン名]]を [[FQDN]] と呼び、
そうでないものは [[FQDN]] でないと言う人もいます。

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[FIGCAPTION[
[5] [CITE@en[RFC 7622 - Extensible Messaging and Presence Protocol (XMPP): Address Format]]
([TIME[2015-12-08 07:08:54 +09:00]] 版)
<https://tools.ietf.org/html/rfc7622>
]FIGCAPTION]

> 
>       Informational Note: The term "fully qualified domain name" is not
>       well defined.  In '''['''RFC1034''']''', it is also called an absolute domain
>       name, and the two terms are associated in '''['''RFC1535''']'''.  The earliest
>       use of the term can be found in '''['''RFC1123''']'''.  References to those
>       older specifications ought not to be construed as limiting the
>       characters of a fully qualified domain name to the ASCII range;
>       for example, '''['''RFC5890''']''' mentions that a fully qualified domain name
>       can contain one or more U-labels.
> 

]FIG]


[FIG(quote)[
[FIGCAPTION[
[6] [CITE@en[RFC 7719 - DNS Terminology]]
( ([TIME[2016-06-05 17:09:11 +09:00]]))
<https://tools.ietf.org/html/rfc7719#section-2>
]FIGCAPTION]

> 
>    Fully qualified domain name (FQDN):  This is often just a clear way
>       of saying the same thing as "domain name of a node", as outlined
>       above.  However, the term is ambiguous.  Strictly speaking, a
>       fully qualified domain name would include every label, including
>       the final, zero-length label of the root: such a name would be
>       written "www.example.net." (note the terminating dot).  But
>       because every name eventually shares the common root, names are
>       often written relative to the root (such as "www.example.net") and
>       are still called "fully qualified".  This term first appeared in
>       '''['''RFC819''']'''.  In this document, names are often written relative to
>       the root.
>       The need for the term "fully qualified domain name" comes from the
>       existence of partially qualified domain names, which are names
>       where some of the right-most names are left off and are understood
>       only by context.

]FIG]