Depreciation

The word depreciation literally, by the struct we of the word, means "decline in price". It refers, in usage, to decrease in the value of assets - fixed assets and capital assets. This decrease occurs (gradually and permanent ally) due to wear and tear when used in productive activities, passage of time (even with un-use), obsolescence, depletion (or exhaustion), or any other cause. It is meant to quantify (through policy basis) the permanent and continuous diminution in the quality, and quantity or the value of an asset. It is a measure of the exhaustion of the effective or used an asset from any cause during a given period and continues upto the end of the life of the asset. 

Machinery, furniture, transport vehicles, etc. depreciate by constant use (and even non-use, with passage of time). Buildings and open air structures depreciate with passage of time. Mines decline in asset value by depletion. Accidents also cause decrease in asset value in their wake. Sluggish 01. bearish markets are associated with a permanent fall in prices of an asset, i.e. its value goes down or depreciates, as in cases of investments, residential property (under an adverse environment, say, an epidemic, large scale migration, etc.).