The Collaborative International Dictionary of English v.0.48:

Tolerance \Tol"er*ance\, n. [L. tolerantia: cf. F.
   tol['e]rance.]
   1. The power or capacity of enduring; the act of enduring;
      endurance.
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            Diogenes, one frosty morning, came into the market
            place, shaking, to show his tolerance. --Bacon.
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   2. The endurance of the presence or actions of objectionable
      persons, or of the expression of offensive opinions;
      toleration.
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   3. (Med.) The power possessed or acquired by some persons of
      bearing doses of medicine which in ordinary cases would
      prove injurious or fatal.
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   4. (Forestry) Capability of growth in more or less shade.
      [Webster 1913 Suppl.]

   5. the allowed amount of variation from the standard or from
      exact conformity to the specified dimensions, weight,
      hardness, voltage etc., in various mechanical or
      electrical devices or operations; -- caklled also
      allowance specif.: (Coinage) The amount which coins,
      either singly or in lots, are legally allowed to vary
      above or below the standard of weight or fineness.
      [Webster 1913 Suppl. +PJC]

   6. (Biochemistry) the capacity to resist the deleterious
      action of a chemical agent normally harmful to the
      organism; as, the acquired tolerance of bacteria to
      anitbiotics.
      [PJC]

   7. (Immunology) the acquired inability to respond with an
      immune reaction to an antigen to which the organism
      normally responds; -- called also immunotolerance,
      immunological tolerance, or immune tolerance. Such
      tolerance may be induced by exposing an animal to the
      antigen at a very early stage of life, prior to maturation
      of the immune system, or, in adults, by exposing the
      animal to repeated low doses of a weak protein antigen
      (low-zone tolerance), or to a large amount of an antigen
      (high-zone tolerance).
      [PJC]

   Tolerance of the mint. (Coinage) Same as Remedy of the
      mint. See under Remedy.
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The Collaborative International Dictionary of English v.0.48:

Allowance \Al*low"ance\, n. [OF. alouance.]
   1. Approval; approbation. [Obs.] --Crabbe.
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   2. The act of allowing, granting, conceding, or admitting;
      authorization; permission; sanction; tolerance.
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            Without the king's will or the state's allowance.
                                                  --Shak.
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   3. Acknowledgment.
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            The censure of the which one must in your allowance
            o'erweigh a whole theater of others.  --Shak.
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   4. License; indulgence. [Obs.] --Locke.
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   5. That which is allowed; a share or portion allotted or
      granted; a sum granted as a reimbursement, a bounty, or as
      appropriate for any purpose; a stated quantity, as of food
      or drink; hence, a limited quantity of meat and drink,
      when provisions fall short.
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            I can give the boy a handsome allowance.
                                                  --Thackeray.
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   6. Abatement; deduction; the taking into account of
      mitigating circumstances; as, to make allowance for the
      inexperience of youth.
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            After making the largest allowance for fraud.
                                                  --Macaulay.
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   7. (com.) A customary deduction from the gross weight of
      goods, different in different countries, such as tare and
      tret.
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The Collaborative International Dictionary of English v.0.48:

Allowance \Al*low"ance\, v. t. [imp. & p. p. Allowancing.]
   [See Allowance, n.]
   To put upon a fixed allowance (esp. of provisions and drink);
   to supply in a fixed and limited quantity; as, the captain
   was obliged to allowance his crew; our provisions were
   allowanced.
   [1913 Webster]

WordNet (r) 3.0 (2006):

allowance
    n 1: an amount allowed or granted (as during a given period);
         "travel allowance"; "my weekly allowance of two eggs"; "a
         child's allowance should not be too generous"
    2: a sum granted as reimbursement for expenses
    3: an amount added or deducted on the basis of qualifying
       circumstances; "an allowance for profit" [syn: allowance,
       adjustment]
    4: a permissible difference; allowing some freedom to move
       within limits [syn: allowance, leeway, margin,
       tolerance]
    5: a reserve fund created by a charge against profits in order
       to provide for changes in the value of a company's assets
       [syn: valuation reserve, valuation account, allowance,
       allowance account]
    6: the act of allowing; "He objected to the allowance of smoking
       in the dining room"
    v 1: put on a fixed allowance, as of food