A Bank Holiday is exactly what it sounds like - it's a day when banks are closed. In the United States, the most recent bank holiday was Monday, February 20, which was the legal holiday called President's Day - a combined celebration of the February 12 birthday of President Lincoln and the February 22 birthday of President Washington. Some years ago, the two remembrances were combined into one day, celebrated on the third Monday of February to create a three-day weekend. Most bank holidays in the United States are legal holidays, recognized by the government, which means that governmental offices are also closed on those days. Other public services, such as libraries, may or may not close on bank holidays.
The idea of a "bank holiday" dates back to England and the Bank Holidays Act of 1871.