An index used to establish the interest rate of some adjustable rate mortgages (ARM). LIBOR is the London Inter-Bank Offered Rates. This is the interest rate at which the highest rated banks offer to lend to one another in eurodollars. LIBOR offers various maturities, including 1-month, 3-month, 6-month and 1-year, however, the 6-month index is most common for mortgages. LIBOR is quoted daily in the Wall Street Journal’s Money Rates.