Straightforward enough, catastrophe in English is a sudden disaster or misfortune and καταστροφή in Greek is destruction, collapse, disaster. Clearly not a word that has changed much in moving from one language to another.
My Chambers dictionary says catastrophe derives from κατά, the Greek for down, and strophe, in Greek στροφή, meaning turning.
My favourite use of the word comes from a plumber I know here on Skopelos who describes difficult plumbing situations as a catastrophe. Particularly difficult plumbing situations he describes as "the full catastrophe". One hopes to avoid those wherever possible.
This particular plumber once explained to me his theory on learning English. "When you have listened to Eric Clapton, Elton John and Rod Stewart, then you can speak English," he stated with absolute conviction, at which point his apprentice added "...and Rory Gallagher". This idea of teaching English using ageing, and in one case dead, rockers is a new one on me, but it's certainly worth a try. What do you think, Mr Gove?