Comment by JackFr

It measures the answer to the hypothetical question "If a another bank with good credit came to you right now to borrow (overnight/1W/1M/3M) in (USD/EUR/GBP/CHF/JPY) what rate would you offer them?" Which is a proxy for the banks' willingless to lend. (It had a less quoted counterpart, LIBID the London Interbank Bid Rate, where would you borrow at.)