term:

Boot

boot n

[obsolete or dialect boot compensation, from Old English bōt advantage, compensation]
: additional money or property received to make up the difference in an exchange of business or investment property that is of like kind but unequal in value NOTE: Under Internal Revenue Code section 1031, no tax liability results from an exchange solely of like-kind property used in a business or trade or held for investment. If the exchange includes boot, however, under section 1245 the boot will be treated as ordinary income.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.