The Collaborative International Dictionary of English v.0.48:

Expense \Ex*pense"\, n. [L. expensa (sc. pecunia), or expensum,
   fr. expensus, p. p. of expendere. See Expend.]
   1. A spending or consuming; disbursement; expenditure.
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            Husband nature's riches from expense. --Shak.
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   2. That which is expended, laid out, or consumed; cost;
      outlay; charge; -- sometimes with the notion of loss or
      damage to those on whom the expense falls; as, the
      expenses of war; an expense of time.
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            Courting popularity at his party's expense.
                                                  --Brougham.
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   3. Loss. [Obs.] --Shak.
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            And moan the expense of many a vanished sight.
                                                  --Spenser.
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   Expense magazine (Mil.), a small magazine containing
      ammunition for immediate use. --H. L. Scott.
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WordNet (r) 3.0 (2006):

expense
    n 1: amounts paid for goods and services that may be currently
         tax deductible (as opposed to capital expenditures) [syn:
         expense, disbursal, disbursement]
    2: a detriment or sacrifice; "at the expense of"
    3: money spent to perform work and usually reimbursed by an
       employer; "he kept a careful record of his expenses at the
       meeting"
    v 1: reduce the estimated value of something; "For tax purposes
         you can write off the laser printer" [syn: expense,
         write off, write down]