Greek and Latin Roots of English: Disaster

According to the Merriam-Webster Dictionary disaster is "something (such as a flood, tornado, fire, plane crash, etc.) that happens suddendly and causes much suffering or loss to many people.

Disaster derives from Middle French and Old Italian; Middle French desastre, from Old Italian disastro, from comes from the Greek pejorative prefix dus- "bad", and aster-/astro- "star". 

Another words with the root astro- are: asteroid, astrolab and astrology. Other words with the root dis- are: disassociate, disambiguate and disorientate.

Greek and Latin Roots of English: Disaster