Where does the term "boot" come from...?

Boot is the term used by the IRS and tax professionals when they talk about the taxable portion of a 1031 exchange. But where does it come from?--it's not defined anywhere in the internal revenue code, or in any court cases.

There are several theories, but the one that we think is probably correct goes back to the beginning of this country when people commonly traded things like horses and cattle. If the two parties determined that one horse, for example, was worth more than the other, the person that received the more valuable horse had to pay something to the other (money, tobacco, sugar, etc.) to even the score, and the additional item went into the recipients boot--hence the term.

--The Experts