Is there a reason people say Meerus?

There’s alot of things DB fans say that confuses me, half the things I hear are made up from the fandom. The reason this one confuses me in particular is because he has an official name. It’s not like zenkai that’s completely made up or TUI which is a fandom name based off of a misunderstanding. Merus is never spelt like that… is there any reason why people say Meerus?