Black Monday (1) A name for Easter Monday, in remembrance of the dreadful experiences of Edward III., before Paris, on Easter Monday, April 14, 1360. Many soldiers and horses perished from the extreme cold. (2) The 27th of Feb., 1865, a memorable day in Melbourne, Australia, when a destructive sirocco prevailed in the surrounding country.
Entry from Everybody's Cyclopedia, 1912.