How could Zuffa "own" the word submission?

There was a text at the end of one promotional video for the ufc,stating that the word "submission" is a "registered trademark". How is this possible? That's not a name,nor a product. They did not invent this word, it's part of the language and as such it existed long before any of the owners of zuffa was born. Is it possible in the US to copyright a normal, regular word? If someone copyrights words, that are vital for the industry and our lives like money and electricity how would society work?