Or London Inter Bank Offer Rate is the rate at which banks agree to lend to each other at on a wholesale basis. There is normally a time period attached to it to confirm the borrowing term; e.g. overnight, 1 month, 3 month, 6 month, etc. The most typically applied rate is 3 Month Libor. It is used a lot by Private Banks, in Commercial Mortgages and Development Finance as their Cost of Funds.