a calamitous event, esp. one occurring suddenly and causing great loss of life, damage, or hardship, as a flood, airplane crash, or business failure.
2.
Obsolete. an unfavorable aspect of a star or planet.
Origin: 1585–95; < MF desastre < It disastro, equiv. to dis-dis-1+ astro star < L astrum < Gk ástron
Synonyms: 1.mischance, misfortune, misadventure, mishap, accident, blow, reverse, adversity, affliction. Disaster,calamity,catastrophe,cataclysm refer to adverse happenings often occurring suddenly and unexpectedly. A disaster may be caused by carelessness, negligence, bad judgment, or the like, or by natural forces, as a hurricane or flood: a railroad disaster. Calamity suggests great affliction, either personal or general; the emphasis is on the grief or sorrow caused: the calamity of losing a child. Catastrophe refers esp. to the tragic outcome of a personal or public situation; the emphasis is on the destruction or irreplaceable loss: the catastrophe of a defeat in battle. Cataclysm, physically an earth-shaking change, refers to a personal or public upheaval of unparalleled violence: a cataclysm that turned his life in a new direction.
An occurrence causing widespread destruction and distress; a catastrophe.
A grave misfortune.
Informal A total failure: The dinner party was a disaster.
Obsolete An evil influence of a star or planet.
[French désastre, from Italian disastro : dis-, pejorative pref. (from Latin dis-; see dis-) + astro, star (from Latin astrum, from Greek astron; see ster-3 in Indo-European roots).]
1580, from M.Fr. desastre (1564), from It. disastro "ill-starred," from dis- "away, without" + astro "star, planet," from L. astrum, from Gk. astron. The sense is astrological, of a calamity blamed on an unfavorable position of a planet.