The Collaborative International Dictionary of English v.0.48:

mailing list \mailing list\ n.
   A list of names and addresses to which advertising,
   solicitations of money, or other materials material sent in
   large quantities is mailed; -- it is usually used by
   comercial or charitable organizations. Mailing lists are
   often sold by organizations to other organizations, and are
   frequently used for targeted mailing, i. e., mailing to
   groups of people who are more likely htan the general
   population to respond as desired to the message in the mail.
   [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

mailing list
    n 1: a list of names and addresses to which advertising material
         is mailed

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "mailing list":
   PP, RD, RFD, airmail, book post, correspondence, direct mail,
   direct-mail selling, express, fourth-class mail, frank,
   halfpenny post, junk mail, letter post, letters, mail,
   mail-order selling, newspaper post, parcel post, post, post day,
   registered mail, rural delivery, rural free delivery, sea mail,
   seapost, special delivery, special handling, surface mail



The Jargon File (version 4.4.7, 29 Dec 2003):

mailing list
 n.

    (often shortened in context to list)

    1. An email address that is an alias (or macro, though that word is
    never used in this connection) for many other email addresses. Some mailing
    lists are simple reflectors, redirecting mail sent to them to the list of
    recipients. Others are filtered by humans or programs of varying degrees of
    sophistication; lists filtered by humans are said to be moderated.

    2. The people who receive your email when you send it to such an address.

    Mailing lists are one of the primary forms of hacker interaction, along
    with Usenet. They predate Usenet, having originated with the first UUCP
    and ARPANET connections. They are often used for private
    information-sharing on topics that would be too specialized for or
    inappropriate to public Usenet groups. Though some of these maintain almost
    purely technical content (such as the Internet Engineering Task Force
    mailing list), others (like the ?sf-lovers? list maintained for many years
    by Saul Jaffe) are recreational, and many are purely social. Perhaps the
    most infamous of the social lists was the eccentric bandykin distribution;
    its latter-day progeny, lectroids and tanstaafl, still include a number of
    the oddest and most interesting people in hackerdom.

    Mailing lists are easy to create and (unlike Usenet) don't tie up a
    significant amount of machine resources (until they get very large, at
    which point they can become interesting torture tests for mail software).
    Thus, they are often created temporarily by working groups, the members of
    which can then collaborate on a project without ever needing to meet
    face-to-face. Much of the material in this lexicon was criticized and
    polished on just such a mailing list (called ?jargon-friends?), which
    included all the co-authors of Steele-1983.


The Free On-line Dictionary of Computing (30 December 2018):

mailing list

    (Often shortened in context to "list") An
   electronic mail address that is an alias (or macro, though
   that word is never used in this connection) which is expanded
   by a mail exploder to yield many other e-mail addresses.
   Some mailing lists are simple "reflectors", redirecting mail
   sent to them to the list of recipients.  Others are filtered
   by humans or programs of varying degrees of sophistication;
   lists filtered by humans are said to be "moderated".

   The term is sometimes used, by extension, for the people who
   receive e-mail sent to such an address.

   Mailing lists are one of the primary forms of hacker
   interaction, along with Usenet.  They predate Usenet,
   having originated with the first UUCP and ARPANET
   connections.  They are often used for private
   information-sharing on topics that would be too specialised
   for or inappropriate to public Usenet groups.  Though some
   of these maintain almost purely technical content (such as the
   Internet Engineering Task Force mailing list), others (like
   the "sf-lovers" list maintained for many years by Saul Jaffe)
   are recreational, and many are purely social.  Perhaps the
   most infamous of the social lists was the eccentric bandykin
   distribution; its latter-day progeny, lectroids and
   tanstaafl, still include a number of the oddest and most
   interesting people in hackerdom.

   Mailing lists are easy to create and (unlike Usenet) don't
   tie up a significant amount of machine resources (until they
   get very large, at which point they can become interesting
   torture tests for mail software).  Thus, they are often
   created temporarily by working groups, the members of which
   can then collaborate on a project without ever needing to meet
   face-to-face.

   There are several programs to automate mailing list
   maintenance, e.g. Listserv, Listproc, Majordomo.

   Requests to subscribe to, or leave, a mailing list should
   ALWAYS be sent to the list's "-request" address (e.g.
   ietf-request@cnri.reston.va.us for the IETF mailing list).
   This prevents them being sent to all recipients of the list
   and ensures that they reach the maintainer of the list, who
   may not actually read the list.

   [Jargon File]

   (2001-04-27)