Holocaust trivialization is the use of the word holocaust in a way that decreases the perceived size or importance of the Holocaust: the genocide of six million European Jews during World War II.
Originally, the word used to mean a (religious) sacrifice that is burnt completely to ash, but gained a new meaning something along the lines of "the large-scale destruction of a group of humans or animals" at some point during the late 19th century. For example, in 1915 the Armenian Genocide was described as a holocaust by many people of the time.
These usages are seen as offensive by many authors and scholars. Holocaust survivor Elie Wiesel has said that the word has become too trivialized, using examples like news networks talking about the defeat of a sports team, or the murder of six people, and calling it a holocaust.