"Reich" is some gay ethno-nationalistic shit that Hitler cribbed from Arthur Moeller van den Bruck. Supposedly, the Holy Roman Empire was the first Reich, and the German Empire that ended in 1918 was the second. The fourth is some hypothetical bogeyman that Antifa is working to stop... I guess.
However, I don't know any credible historian that refers to the Holy Roman Empire as the "First Reich." Although many are quick to point out it wasn't very holy, certainly wasn't Roman, and was a pretty crappy empire.
Point being, anybody that uses that term to describe anything that isn't Nazi Germany (the "Third Reich"), is usually a fucking idiot, and should be ridiculed mercilessly. Ironically, they're using the very language Hitler would want them to use. Dumbasses.