The Collaborative International Dictionary of English v.0.48:

Chat \Chat\ (ch[a^]t), v. i. [imp. & p. p. Chatted; p. pr. &
   vb. n. Chatting.] [From Chatter. [root]22.]
   To talk in a light and familiar manner; to converse without
   form or ceremony; to gossip. --Shak.
   [1913 Webster]

         To chat a while on their adventures.     --Dryden.

   Syn: To talk; chatter; gossip; converse.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chat \Chat\, v. t.
   To talk of. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chat \Chat\, n.
   1. Light, familiar talk; conversation; gossip.
      [1913 Webster]

            Snuff, or fan, supply each pause of chat,
            With singing, laughing, ogling, and all that.
                                                  --Pope.
      [1913 Webster]

   2. (Zool.) A bird of the genus Icteria, allied to the
      warblers, in America. The best known species are the
      yellow-breasted chat (Icteria viridis), and the
      long-tailed chat (Icteria longicauda). In Europe the
      name is given to several birds of the family
      Saxicolid[ae], as the stonechat, and whinchat.
      [1913 Webster]

   Bush chat. (Zool.) See under Bush.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chat \Chat\, n.
   1. A twig, cone, or little branch. See Chit.
      [1913 Webster]

   2. pl. (Mining) Small stones with ore.
      [1913 Webster]

   Chat potatoes, small potatoes, such as are given to swine.
      [Local.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

chat
    n 1: an informal conversation [syn: chat, confab,
         confabulation, schmooze, schmoose]
    2: birds having a chattering call [syn: New World chat,
       chat]
    3: songbirds having a chattering call [syn: Old World chat,
       chat]
    v 1: talk socially without exchanging too much information; "the
         men were sitting in the cafe and shooting the breeze" [syn:
         chew the fat, shoot the breeze, chat, confabulate,
         confab, chitchat, chit-chat, chatter, chaffer,
         natter, gossip, jaw, claver, visit]

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "chat":
   babble, babblement, bavardage, be closeted with, bibble-babble,
   blab, blabber, blah-blah, blather, blether, blethers, bull session,
   bullshit, burble, cackle, caquet, caqueterie, causerie, chatter,
   chew the fat, chin, chitter-chatter, clack, clatter, colloque,
   colloquy, compare, confab, confabulate, confabulation,
   conversation, converse, coze, cozy chat, dialogue, dish, dither,
   entice, flirt with, friendly chat, gab, gabble, gam, gas, gibber,
   gibble-gabble, go on, gossip, guff, gush, haver, heart-to-heart,
   heart-to-heart talk, hot air, idle talk, induce, inveigle, jabber,
   jaw, lallygag, little talk, lure, make conversation, mere talk,
   natter, nonsense talk, palaver, parley, patter, persuade,
   pour forth, prate, prating, prattle, prevail upon, prittle-prattle,
   proposition, prose, ramble on, rap, rap session, rattle, rattle on,
   reel off, run on, seduce, shoot the breeze, small talk, smatter,
   spout, spout off, talk, talk away, talk nonsense, talk on,
   talkee-talkee, tempt, tete-a-tete, tinkle, tittle-tattle, twaddle,
   twattle, twiddle, twitter, visit, waffle, yak, yakkety-yak, yammer,
   yap, yarn



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

chat

    Any system that allows any number of
   logged-in users to have a typed, real-time, on-line
   conversation via a network.

   The medium of chat is descended from talk, but the terms
   (and the media) have been distinct since at least the early
   1990s.  talk is prototypically for a small number of people,
   generally with no provision for channels.  In chat
   systems, however, there are many channels in which any
   number of people can talk; and users may send private
   (one-to-one) messages.

   Some early chat systems (in use 1998) include IRC, ICQ and
   Palace.  More recent alternatives include MSN Messenger
   and Google Talk.

   Chat systems have given rise to a distinctive style combining
   the immediacy of talking with all the precision (and
   verbosity) that written language entails.  It is difficult to
   communicate inflection, though conventions have arisen to help
   with this.

   The conventions of chat systems include special items of
   jargon, generally abbreviations meant to save typing, which
   are not used orally.  E.g. BCNU, BBL, BTW, CUL,
   FWIW, FYA, FYI, IMHO, OT, OTT, TNX, WRT,
   WTF, WTH, , , BBL, HHOK, NHOH, ROTFL,
   AFK, b4, TTFN, TTYL, OIC, re.

   Much of the chat style is identical to (and probably derived
   from) Morse code jargon used by ham-radio amateurs since the
   1920s, and there is, not surprisingly, some overlap with TDD
   jargon.  Most of the jargon was in use in talk systems.
   Many of these expressions are also common in Usenet news
   and electronic mail and some have seeped into popular
   culture, as with emoticons.

   The MUD community uses a mixture of emoticons, a few of
   the more natural of the old-style talk mode abbreviations,
   and some of the "social" list above.  In general, though,
   MUDders express a preference for typing things out in full
   rather than using abbreviations; this may be due to the
   relative youth of the MUD cultures, which tend to include many
   touch typists.  Abbreviations specific to MUDs include:
   FOAD, ppl (people), THX (thanks), UOK? (are you OK?).

   Some BIFFisms (notably the variant spelling "d00d") and
   aspects of ASCIIbonics appear to be passing into wider use
   among some subgroups of MUDders and are already pandemic on
   chat systems in general.

   See also hakspek.

   Suck article "Screaming in a Vacuum"
   (http://suck.com/daily/96/10/23/).

   (2006-05-31)