The Collaborative International Dictionary of English v.0.48:

Advent \Ad`vent\, n. [L. adventus, fr. advenire, adventum: cf.
   F. avent. See Advene.]
   1. (Eccl.) The period including the four Sundays before
      Christmas.
      [1913 Webster]

   Advent Sunday (Eccl.), the first Sunday in the season of
      Advent, being always the nearest Sunday to the feast of
      St. Andrew (Now. 30). --Shipley.
      [1913 Webster]

   2. The first or the expected second coming of Christ.
      [1913 Webster]

   3. Coming; any important arrival; approach.
      [1913 Webster]

            Death's dreadful advent.              --Young.
      [1913 Webster]

            Expecting still his advent home.      --Tennyson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

advent
    n 1: arrival that has been awaited (especially of something
         momentous); "the advent of the computer" [syn: advent,
         coming]
    2: the season including the four Sundays preceding Christmas
    3: (Christian theology) the reappearance of Jesus as judge for
       the Last Judgment [syn: Second Coming, Second Coming of
       Christ, Second Advent, Advent, Parousia]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "Advent":
   Allhallowmas, Allhallows, Allhallowtide, Annunciation,
   Annunciation Day, Ascension Day, Ash Wednesday, Candlemas,
   Candlemas Day, Carnival, Christmas, Corpus Christi, Easter,
   Easter Monday, Easter Saturday, Easter Sunday, Eastertide,
   Ember days, Epiphany, Good Friday, Halloween, Hallowmas,
   Holy Thursday, Holy Week, Lady Day, Lammas, Lammas Day, Lammastide,
   Lent, Lententide, Mardi Gras, Martinmas, Maundy Thursday,
   Michaelmas, Michaelmas Day, Michaelmastide, Palm Sunday,
   Pancake Day, Passion Week, Pentecost, Quadragesima,
   Quadragesima Sunday, Septuagesima, Shrove Tuesday, Trinity Sunday,
   Twelfth-day, Twelfth-tide, Whit-Tuesday, White Sunday, Whitmonday,
   Whitsun, Whitsunday, Whitsuntide, Whitweek



Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "advent":
   access, accession, accomplishment, achievement, advance, afflux,
   affluxion, appearance, approach, approach of time, approaching,
   appropinquation, approximation, appulse, arrival, attainment,
   coming, coming near, coming toward, flowing toward, forthcoming,
   imminence, nearing, nearness, oncoming, proximation, reaching,
   time drawing on



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

ADVENT
 /ad'vent/, n.

    The prototypical computer adventure game, first designed by Will Crowther
    on the PDP-10 in the mid-1970s as an attempt at computer-refereed fantasy
    gaming, and expanded into a puzzle-oriented game by Don Woods at Stanford
    in 1976. (Woods had been one of the authors of INTERCAL.) Now better
    known as Adventure or Colossal Cave Adventure, but the TOPS-10 operating
    system permitted only six-letter filenames in uppercase. See also vadding
    , Zork, and Infocom.

    Figure 1. Screen shot of the original ADVENT game

    Orange River Chamber
    You are in a splendid chamber thirty feet high. The walls are frozen rivers
of
    orange stone. An awkward canyon and a good passage exit from east and west
    sidesof the chamber.

    A cheerful little bird is sitting here singing.

    >drop rod
    Dropped.

    >take bird
    You catch the bird in the wicker cage.

    >take rod
    Taken.

    >w
    At Top of Small Pit
    At your feet is a small pit breathing traces of white mist. A west passage
ends
    here except for a small crack leading on.

    Rough stone steps lead down the pit.

    >down

    In Hall of Mists
    You are at one end of a vast hall stretching forward out of sight to the
west.
    There are openings to either side. Nearby, a wide stone staircase leads
    downward. The hall is filled with wisps of white mist swaying to and fro
almost
    as if alive. A cold wind blows up the staircase. There is a passage at the
top
    of a dome behind you.

    Rough stone steps lead up the dome.


    This game defined the terse, dryly humorous style since expected in text
    adventure games, and popularized several tag lines that have become
    fixtures of hacker-speak: ?A huge green fierce snake bars the way!? ?I see
    no X here? (for some noun X). ?You are in a maze of twisty little passages,
    all alike.? ?You are in a little maze of twisty passages, all different.?
    The ?magic words? xyzzy and plugh also derive from this game.

    Crowther, by the way, participated in the exploration of the Mammoth &
    Flint Ridge cave system; it actually has a Colossal Cave and a Bedquilt as
    in the game, and the Y2 that also turns up is cavers' jargon for a map
    reference to a secondary entrance.

    ADVENT sources are available for FTP at ftp://ftp.wustl.edu/doc/misc/
    if-archive/games/source/advent.tar.Z. You can also play it as a Java applet
    . There is a good page of resources at the Colossal Cave Adventure Page.


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

ADVENT

    /ad'vent/ The prototypical computer adventure game,
   first implemented by Will Crowther for a CDC computer
   (probably the CDC 6600?) as an attempt at computer-refereed
   fantasy gaming.

   ADVENT was ported to the PDP-10, and expanded to the
   350-point Classic puzzle-oriented version, by Don Woods of
   the Stanford Artificial Intelligence Laboratory (SAIL).  The
   game is now better known as Adventure, but the TOPS-10
   operating system permitted only six-letter filenames.  All
   the versions since are based on the SAIL port.

   David Long of the University of Chicago Graduate School of
   Business Computing Facility (which had two of the four
   DEC20s on campus in the late 1970s and early 1980s) was
   responsible for expanding the cave in a number of ways, and
   pushing the point count up to 500, then 501 points.  Most of
   his work was in the data files, but he made some changes to
   the parser as well.

   This game defined the terse, dryly humorous style now expected
   in text adventure games, and popularised several tag lines
   that have become fixtures of hacker-speak: "A huge green
   fierce snake bars the way!"  "I see no X here" (for some noun
   X).  "You are in a maze of twisty little passages, all alike."
   "You are in a little maze of twisty passages, all different."
   The "magic words" xyzzy and plugh also derive from this
   game.

   Crowther, by the way, participated in the exploration of the
   Mammoth & Flint Ridge cave system; it actually *has* a
   "Colossal Cave" and a "Bedquilt" as in the game, and the "Y2"
   that also turns up is cavers' jargon for a map reference to a
   secondary entrance.

   See also vadding.

   [Was the original written in Fortran?]

   [Jargon File]

   (1996-04-01)