WordNet (r) 3.0 (2006):

Spam
    n 1: a canned meat made largely from pork
    2: unwanted e-mail (usually of a commercial nature sent out in
       bulk) [syn: spam, junk e-mail]
    v 1: send unwanted or junk e-mail

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SPAM
       Send Phenomenal Amounts of Mail (Usenet, EMP, slang)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SPAM
       Spiced Pork and hAM (Usenet, EMP)


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

spam
 vt.,vi.,n.

    [from Monty Python's Flying Circus]

    1. To crash a program by overrunning a fixed-size buffer with excessively
    large input data. See also buffer overflow, overrun screw, smash the
    stack.

    2. To cause a newsgroup to be flooded with irrelevant or inappropriate
    messages. You can spam a newsgroup with as little as one well- (or ill-)
    planned message (e.g. asking ?What do you think of abortion?? on
    soc.women). This is often done with cross-posting (e.g. any message which
    is cross-posted to alt.rush-limbaugh and alt.politics.homosexuality will
    almost inevitably spam both groups). This overlaps with troll behavior;
    the latter more specific term has become more common.

    3. To send many identical or nearly-identical messages separately to a
    large number of Usenet newsgroups. This is more specifically called ECP,
    Excessive Cross-Posting. This is one sure way to infuriate nearly everyone
    on the Net. See also velveeta and jello.

    4. To bombard a newsgroup with multiple copies of a message. This is more
    specifically called EMP, Excessive Multi-Posting.

    5. To mass-mail unrequested identical or nearly-identical email messages,
    particularly those containing advertising. Especially used when the mail
    addresses have been culled from network traffic or databases without the
    consent of the recipients. Synonyms include UCE, UBE. As a noun, ?spam?
    refers to the messages so sent.

    6. Any large, annoying, quantity of output. For instance, someone on IRC
    who walks away from their screen and comes back to find 200 lines of text
    might say ?Oh no, spam?.

    The later definitions have become much more prevalent as the Internet has
    opened up to non-techies, and to most people senses 3 4 and 5 are now
    primary. All three behaviors are considered abuse of the net, and are
    almost universally grounds for termination of the originator's email
    account or network connection. In these senses the term ?spam? has gone
    mainstream, though without its original sense or folkloric freight ? there
    is apparently a widespread myth among lusers that ?spamming? is what
    happens when you dump cans of Spam into a revolving fan. Hormel, the makers
    of Spam, have published a surprisingly enlightened position statement on
    the Internet usage.


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

spam
spamming

   1.  (From Hormel's Spiced Ham, via the Monty Python
   "Spam" song) To post irrelevant or inappropriate messages to
   one or more Usenet newsgroups, mailing lists, or other
   messaging system in deliberate or accidental violation of
   netiquette.

   It is possible to spam a newsgroup with one well- (or ill-)
   planned message, e.g. asking "What do you think of abortion?"
   on soc.women.  This can be done by cross-posting, e.g. any
   message which is crossposted to alt.rush-limbaugh and
   alt.politics.homosexuality will almost inevitably spam both
   groups.  (Compare troll and flame bait).

   Posting a message to a significant proportion of all
   newsgroups is a sure way to spam Usenet and become an object
   of almost universal hatred.  Canter and Siegel spammed the net
   with their Green card post.

   If you see an article which you think is a deliberate spam, DO
   NOT post a follow-up - doing so will only contribute to the
   general annoyance.  Send a polite message to the poster by
   private e-mail and CC it to "postmaster" at the same address.
   Bear in mind that the posting's origin might have been forged
   or the apparent sender's account might have been used by
   someone else without his permission.

   The word was coined as the winning entry in a 1937 competition
   to choose a name for Hormel Foods Corporation's "spiced meat"
   (now officially known as "SPAM luncheon meat").  Correspondant
   Bob White claims the modern use of the term predates Monty
   Python by at least ten years.  He cites an editor for the
   Dallas Times Herald describing Public Relations as "throwing a
   can of spam into an electric fan just to see if any of it
   would stick to the unwary passersby."

   Usenet newsgroup: news:news.admin.net-abuse.

   See also netiquette.

   2. (A narrowing of sense 1, above) To indiscriminately send
   large amounts of unsolicited e-mail meant to promote a
   product or service.  Spam in this sense is sort of like the
   electronic equivalent of junk mail sent to "Occupant".

   In the 1990s, with the rise in commercial awareness of the
   net, there are actually scumbags who offer spamming as a
   "service" to companies wishing to advertise on the net.  They
   do this by mailing to collections of e-mail addresses,
   Usenet news, or mailing lists.  Such practises have caused
   outrage and aggressive reaction by many net users against the
   individuals concerned.

   3. (Apparently a generalisation of sense 2, above) To abuse
   any network service or tool by for promotional purposes.

   "AltaVista is an index, not a promotional tool.  Attempts to
   fill it with promotional material lower the value of the index
   for everyone.  [...] We will disallow URL submissions from
   those who spam the index.  In extreme cases, we will exclude
   all their pages from the index." -- Altavista.

   4.  To crash a program by overrunning a
   fixed-size buffer with excessively large input data.

   See also buffer overflow, overrun screw, smash the stack.

   5.  (A narrowing of sense 1, above) To flood any
   chat forum or Internet game with purposefully annoying
   text or macros.  Compare Scrolling.

   (2003-09-21)