A holocaust is an event in which there is a lot of destruction and many people are killed, especially one caused by war.
例句
A nuclear holocaust seemed a very real possibility in the '50s.核災難在20世紀50年代似乎真的非常可能發生。
N-SING
（第二次世界大戰中納粹對猶太人進行的）大屠殺
The Holocaust is used to refer to the killing by the Nazis of millions of Jews during the Second World War.
例句
...an Israeli-based fund for survivors of the Holocaust and their families.設在以色列的為大屠殺幸存者及其家人建立的基金
英漢詞典釋義
n.
大屠殺
The Auschwitz concentration camp always remind the world of the holocaust.奧辛威茨集中營總是讓世人想起大屠殺。It is unthinkable that we shall allow a nuclear holocaust to occur.我們若竟讓核武器大屠殺的慘劇發生，簡直是匪夷所思。