When you think about depletion, think about a resource being decreased. Depletion is usually not a good thing; we worry about the depletion of the ozone and the depletion of the soil.
Have you ever run out of gas or money? Then you know what it's like to be in a state of depletion. Your bank account is in a state of depletion if you've been taking a lot of money out of it. The world's oil reserves are moving closer to depletion as oil runs out. In any type of depletion, something is running low or running out.
