Expense, n.
Etymology: [L. expensa (sc. pecunia), or expensum, fr. expensus, p. p. of expendere. See Expend.]
1. A spending or consuming; disbursement; expenditure. Husband nature's riches from expense. Shak.
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. Courting popularity at his party's expense. Brougham.
3. Loss. [Obs.] Shak. And moan the expense of many a vanished sight. Spenser. Expense magazine (Mil.), a small magazine containing ammunition for immediate use. H. L. Scott.
Shades of meaning
The cost of a thing is whatever one surrenders or gives up for it, intentionally or unintentionally, or even unconsciously; expense is what is laid out by calculation or intention. We say, "he won his fame at the cost of his life;" "I know it to my cost;" we speak of a joke at another's expense; at another's cost would seem to make it a more serious matter. There is a tendency to use cost of what we pay for a possession, expense of what we pay for a service; we speak of the cost of goods, the expense of making up. Outlay is used of some definite expenditure, as for the purchase of supplies; outgo of a steady drain or of incidental expenses. See price.