mandelbug definition: Noun (plural mandelbugs) 1. (computing) A software bug whose behaviour appears to be chaotic. ...
The bloodiest single day of battle was Antietam (26,134 casualties). The bloodiest battle, however - which lasted three days - was Gettysburg (51,112 casualties). July 21, 1861.
The Battle of Shiloh was the bloodiest battle in American history up to that time, although it was superseded the next year by the Battle of Chancellorsville and, soon after, the three-day Battle of Gettysburg, which would prove to be the bloodiest of the war.