Definitions of allowance:

• noun:   the act of allowing

  Example: "He objected to the allowance of smoking in the diningroom"

• noun:   a permissible difference; allowing some freedom to move within limits
• noun:   an amount added or deducted on the basis of qualifying circumstances

  Example: "An allowance for profit"

• noun:   an amount allowed or granted (as during a given period)

  Example: "Travel allowance"

• noun:   a sum granted as reimbursement for expenses
• noun:   a reserve fund created by a charge against profits in order to provide for changes in the value of a company's assets
• verb:   put on a fixed allowance, as of food