term:

Depreciation

depreciation n

1 : any decrease in the value of property (as machinery) for the purpose of taxation that cannot be offset by current repairs and is carried on company books as a yearly charge amortizing the original cost over the useful life of the property

accelerated depreciation
: the depreciation of property that was put into use prior to 1980 which is allowed at a faster rate than normal under the depreciation rules in force before the adoption of the Accelerated Cost Recovery System

straight-line depreciation
: depreciation of an asset by a fixed percentage of its original cost based on its estimated life
2 : a loss in the value of property due to physical deterioration and wear or to obsolescence and lack of adaptability

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.