Definition of Boot:
A boot is any additional value (cash or property) that causes an otherwise tax-free exchexchange
ange to become taxable. For example, if you were performing a like-kind exchange
of a property that you have a $500,000 basis
in, for a property plus cash that gives you a basis of $600,000, you would be taxed on the extra $100,000 (also known as the boot).