Treasury Inflation-Protected Securities are inflation-adjusted bonds issued by the U. S. Treasury. The principal is periodically adjusted for inflation, and the semi-annual fixed interest is paid on the adjusted principal. You pay tax annually on the interest payment. A drawback is that you also pay tax annually on the adjustment to the principal even though you don't receive the adjustment until you cash the bond.
Tips and Gouges
Department of Defense Dictionary of Military and Associated Terms. 31 January 2011.