Quote Originally Posted by JohnQPublic View Post
Actually, I think a holocaust was a specific type of a Judean temple sacrifice (A ram burnt to a crisp or something along that line). So it has been used as a noun for centuries.
If so then the symbol does not relate specifically to an event that happened between 1939 and 1945.

Quote Originally Posted by Etymology Online
holocaust
mid-13c., "sacrifice by fire, burnt offering," from Gk. holokauston "a thing wholly burnt," neut. of holokaustos "burned whole," from holos "whole" (see holo-) + kaustos, verbal adjective of kaiein "to burn." Originally a Bible word for "burnt offerings," given wider sense of "massacre, destruction of a large number of persons" from 1833. The Holocaust "Nazi genocide of European Jews in World War II," first recorded 1957, earlier known in Hebrew as Shoah "catastrophe." The word itself was used in English in reference to Hitler's Jewish policies from 1942, but not as a proper name for them.

Auschwitz makes all too clear the principle that the human psyche can create meaning out of anything. [Robert Jay Lifton, "The Nazi Doctors"]
Perhaps I should have said "proper name" rather than "noun".