A disposition is the permanent withdrawal of property from use in your trade or business or in the production of income. You can make a withdrawal by sale, exchange, retirement, abandonment, or destruction.
You generally recognize gain or loss on the disposition of an asset by sale. However, nonrecognition rules can allow you to postpone some gain. See Publication 544
If you physically abandon property, you can deduct as a loss the adjusted basis of the asset at the time of its abandonment. Your intent must be to discard the asset so that you will not use it again or retrieve it for sale, exchange, or other disposition.
For more information, see IRS Publication 534 Depreciating Property Placed in Service Before 1987
and IRS Publication 544 Sales and Other Dispositions of Assets