Depreciation is a term used in accounting, economics and finance with reference to the fact that assets with finite lives lose value over time. (There is also a separate use in international finance to refer to a reduction in the exchange rate of a currency - see Depreciation (currency)). In accounting, depreciation is a term used to describe any method of attributing the historical or purchase cost of an asset across its useful life, roughly corresponding to normal wear and tear. It is of most use when dealing with assets of a short, fixed service life, and which lose value over that life.
See more at Wikipedia.org...