Depreciation is the systematic and rational allocation of tangible and current asset cost over the periods benefited by the use of the asset.
Depletion is the periodic allocation of the cost of natural resources.
Amortization is the periodic cost allocation process for intangible assets.
Depreciation, depletion and amortization are all periodical allocation of cost of fixed assets, natural resorts and intangible assets respectively and all charged to the revenue account. The difference among these three items are that depreciation, depletion and amortization related to fixed assets, natural resources and intangible assets respectively. Merchandising Transaction