depreciation

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