The Collaborative International Dictionary of English v.0.48:

Token \To"ken\ (t[=o]"k'n), n. [OE. token, taken, AS. t[=a]cen;
   akin to OFries. t[=e]ken, OS. t[=e]kan, D. teeken, G.
   zeichen, OHG. Zeihhan, Icel. t[=a]kan, teiken, Sw. tecken,
   Dan. tegn, Goth. taikns sign, token, gateihan to tell, show,
   AS. te['o]n to accuse, G. zeihen, OHG. z[imac]han, G. zeigen
   to show, OHG. zeig[=o]n, Icel. tj[=a], L. dicere to say, Gr.
   deikny`nai to show, Skr. di[,c]. Cf. Diction, Teach.]
   1. Something intended or supposed to represent or indicate
      another thing or an event; a sign; a symbol; as, the
      rainbow is a token of God's covenant established with
      Noah.
      [1913 Webster]

   2. A memorial of friendship; something by which the
      friendship of another person is to be kept in mind; a
      memento; a souvenir.
      [1913 Webster]

            This is some token from a never friend. --Shak.
      [1913 Webster]

   3. Something given or shown as a symbol or guarantee of
      authority or right; a sign of authenticity, of power, good
      faith, etc.
      [1913 Webster]

            Say, by this token, I desire his company. --Shak.
      [1913 Webster]

   4. A piece of metal intended for currency, and issued by a
      private party, usually bearing the name of the issuer, and
      redeemable in lawful money. Also, a coin issued by
      government, esp. when its use as lawful money is limited
      and its intrinsic value is much below its nominal value.
      [1913 Webster]

   Note: It is now made unlawful for private persons to issue
         tokens.
         [1913 Webster]

   5. (Med.) A livid spot upon the body, indicating, or supposed
      to indicate, the approach of death. [Obs.]
      [1913 Webster]

            Like the fearful tokens of the plague,
            Are mere forerunners of their ends.   --Beau. & Fl.
      [1913 Webster]

   6. (Print.) Ten and a half quires, or, commonly, 250 sheets,
      of paper printed on both sides; also, in some cases, the
      same number of sheets printed on one side, or half the
      number printed on both sides.
      [1913 Webster]

   7. (Ch. of Scot.) A piece of metal given beforehand to each
      person in the congregation who is permitted to partake of
      the Lord's Supper.
      [1913 Webster]

   8. (Mining) A bit of leather having a peculiar mark
      designating a particular miner. Each hewer sends one of
      these with each corf or tub he has hewn.
      [1913 Webster]

   9. (Weaving) In a Jacquard loom, a colored signal to show the
      weaver which shuttle to use.
      [Webster 1913 Suppl.]

   Token money, money which is lawfully current for more than
      its real value. See Token, n., 4.

   Token sheet (Print.), the last sheet of each token. --W.
      Savage.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Token \To"ken\, v. t. [imp. & p. p. Tokened; p. pr. & vb. n.
   Tokening.] [AS. t[=a]cnian, fr. t[=a]cen token. See
   Token, n.]
   To betoken. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

token
    adj 1: insignificantly small; a matter of form only (`tokenish'
           is informal); "the fee was nominal"; "a token gesture of
           resistance"; "a toknenish gesture" [syn: nominal,
           token(a), tokenish]
    n 1: an individual instance of a type of symbol; "the
         word`error' contains three tokens of `r'" [syn: token,
         item]
    2: something serving as a sign of something else
    3: a metal or plastic disk that can be redeemed or used in
       designated slot machines
    4: something of sentimental value [syn: keepsake, souvenir,
       token, relic]

The Free On-line Dictionary of Computing (19 January 2023):

token

   1.  A basic, grammatically indivisible unit of a
   language such as a keyword, operator or identifier.
   Compare: lexeme.

   2.  (Or "pumpkin") An abstract concept passed
   between cooperating agents to ensure synchronised access to a
   shared resource.  Such a token is never duplicated or
   destroyed (unless the resource is) and whoever has the token
   has exclusive access to the resource it controls.  See for
   example token ring.

   If several programmers are working on a program, one
   programmer will "have the token" at any time, meaning that
   only he can change the program whereas others can only read
   it.  If someone else wants to modify it he must first obtain
   the token.

   (1999-02-23)