What term refers to the decrease in value of assets like aircraft and machinery over time?

The term that refers to the decrease in value of assets such as aircraft and machinery over time is depreciation. This concept is essential in accounting and economics because it reflects the wear and tear on physical assets as they are used in business operations. Depreciation accounts for the reduction in value due to factors like age, condition, and obsolescence, allowing businesses to allocate the cost of an asset over its useful life.

This is crucial for financial reporting as it impacts profit calculations and tax liabilities. It also helps in understanding the true economic value of a business's assets over time.

Annuity pertains to a series of equal payments made at regular intervals, which is unrelated to asset value decrease. Depletion usually refers to the reduction in quantity of natural resources like minerals or oil but does not apply to machinery or aircraft. Valuation involves determining the worth of an asset at a particular time, which can include considerations of depreciation but does not specifically denote the decrease in value itself. Thus, the correct term for the decrease in value of tangible depreciable assets is depreciation.