This category of question comes up fairly often.

/u/commiespaceinvader has previously written in response to How accepted is the term 'Holocaust' when used to refer events other than the Nazi genocide of Jews?

/u/kugelfang52 has written about comparing concentration camps to Gulags, and addresses the origins of the word "Holocaust" therein.

/u/peculiarleah has previously answered Why did the term 'The Holocaust' start appearing in its current meaning around the late seventies?

/u/onkelemil has addressed When did people start referring to the Holocaust as "The Holocaust"?