DNS/RFC/7719について、ここに記述してください。

http://www.faqs.org/rfcs/rfc7719.html RFC 7719 - DNS Terminology

   Glue records:  "[Resource records] which are not part of the
      authoritative data [of the zone], and are address resource records
      for the [name servers in subzones].  These RRs are only necessary
      if the name server's name is 'below' the cut, and are only used as
      part of a referral response."  Without glue "we could be faced
      with the situation where the NS RRs tell us that in order to learn
      a name server's address, we should contact the server using the
      address we wish to learn."  (Definition from [RFC1034],
      Section 4.2.1)

      A later definition is that glue "includes any record in a zone
      file that is not properly part of that zone, including nameserver
      records of delegated sub-zones (NS records), address records that
      accompany those NS records (A, AAAA, etc), and any other stray
      data that might appear" ([RFC2181], Section 5.4.1).  Although glue
      is sometimes used today with this wider definition in mind, the
      context surrounding the [RFC2181] definition suggests it is
      intended to apply to the use of glue within the document itself
      and not necessarily beyond.

最後の文が重要だ。"glue"がなにを指すかはその文書できちんと定義して使えと。

このことは次のin-bailiwickにも言えそう。

   In-bailiwick:

      (a) An adjective to describe a name server whose name is either
      subordinate to or (rarely) the same as the zone origin.  In-
      bailiwick name servers require glue records in their parent zone
      (using the first of the definitions of "glue records" in the
      definition above).

      (b) Data for which the server is either authoritative, or else
      authoritative for an ancestor of the owner name.  This sense of
      the term normally is used when discussing the relevancy of glue
      records in a response.  For example, the server for the parent
      zone "example.com" might reply with glue records for
      "ns.child.example.com".  Because the "child.example.com" zone is a
      descendant of the "example.com" zone, the glue records are in-
      bailiwick.

   Out-of-bailiwick:  The antonym of in-bailiwick.