Depreciation - Definition

The gradual loss of value of a building or other property because of age or natural wear. Automobiles in particular depreciate steeply in their first few years. In taxes, this is the deduction you are allowed for the wearing away and expensing over time of such items as office equipment, vehicles, buildings and furniture. For tax purposes, the IRS determines the amount of time such material is expected to last, and you depreciate, or spread the cost of, the asset over its estimated useful life rather than deducting the entire cost in the year you got it.