The Collaborative International Dictionary of English v.0.48:

Sociable \So"cia*ble\, n.
   1. A gathering of people for social purposes; an informal
      party or reception; as, a church sociable. [Colloq. U. S.]
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   2. A carriage having two double seats facing each other, and
      a box for the driver. --Miss Edgeworth.
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The Collaborative International Dictionary of English v.0.48:

Sociable \So"cia*ble\, a.[F., fr. L. sociabilis, fr. sociare to
   associate, fr. socius a companion. See Social.]
   1. Capable of being, or fit to be, united in one body or
      company; associable. [R.]
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            They are sociable parts united into one body.
                                                  --Hooker.
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   2. Inclined to, or adapted for, society; ready to unite with
      others; fond of companions; social.
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            Society is no comfort to one not sociable. --Shak.
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            What can be more uneasy to this sociable creature
            than the dry, pensive retirements of solitude?
                                                  --South.
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   3. Ready to converse; inclined to talk with others; not
      taciturn or reserved.
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   4. Affording opportunites for conversation; characterized by
      much conversation; as, a sociable party.
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   5. No longer hostile; friendly. [Obs.] --Beau. & Fl.
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   Sociable bird, or Sociable weaver (Zool.), a weaver bird
      which builds composite nests. See Republican, n., 3.
      (b) .
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   Syn: Social; companionable; conversible; friendly; familiar;
        communicative; accessible.
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WordNet (r) 3.0 (2006):

sociable
    adj 1: inclined to or conducive to companionship with others; "a
           sociable occasion"; "enjoyed a sociable chat"; "a
           sociable conversation"; "Americans are sociable and
           gregarious" [ant: unsociable]
    2: friendly and pleasant; "a sociable gathering"
    n 1: a party of people assembled to promote sociability and
         communal activity [syn: sociable, social, mixer]

Moby Thesaurus II by Grady Ward, 1.0:

137 Moby Thesaurus words for "sociable":
   Bohemian, accessible, affable, agreeable, all jaw, amiable,
   amicable, approachable, associational, brotherly, candid, casual,
   chatty, chummy, civil, close, clubbable, clubbish, clubby,
   coalitional, communal, communicative, companionable, companionate,
   compatible, congenial, conversable, conversational, convivial,
   cordial, cosy, courteous, degage, demonstrative, easy, easygoing,
   effusive, expansive, extroverted, familiar, favorable,
   fit for society, flip, fluent, folksy, fond of society, frank,
   fraternal, free, free and easy, free-speaking, free-spoken,
   free-tongued, friendlike, friendly, gabby, garrulous, gassy,
   genial, glib, good-natured, gossipy, gracious, gregarious, gushy,
   hail-fellow-well-met, harmonious, haymish, homely, homey,
   hospitable, informal, intimate, irregular, kind, long-winded,
   loose, loquacious, multiloquent, multiloquious, natural,
   neighborlike, neighborly, newsy, offhand, offhanded, open,
   organizational, outgoing, outspoken, overtalkative, peaceable,
   plain, pleasant, prolix, relaxed, self-revealing, self-revelatory,
   simpatico, simple, sisterly, smooth, social, social-minded,
   society, sympathique, talkative, talky, unaffected, unassuming,
   unceremonious, unconstrained, unconventional, unhampered,
   unhostile, unofficial, unrepressed, unreserved, unrestrained,
   unrestricted, unreticent, unsecretive, unshrinking, unsilent,
   unsocial, unstudied, unsuppressed, urbane, verbose, voluble, warm,
   well-affected, well-disposed, well-intentioned, well-meaning,
   well-meant, windy