from the GNU version of the Collaborative International Dictionary of English
- Easter Monday, so called from the severity of that day in 1360, which was so unusual that many of Edward III.'s soldiers, then before Paris, died from the cold.
- The first Monday after the holidays; -- so called by English schoolboys.
Sorry, no etymologies found.
It was a Black Monday indeed.) 'My dear Uncle, ” At three this morning died one of my old scholars, by name George Selwyn Simeona, from Nengone.