Definition of expense:
(n) :
a spending or consuming;
disbursement;
expenditure; 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
"husband nature's riches from expense. - Shakespeare, Sonnet XCIV"
(v) :
to
charge a cost against an expense account; to bill something to the company for which one works
"it should be acceptable to expense a business lunch with a client."