I just found out today, that someone has trademarked the term "tower defense" back in 2008. So, that means Angry Rice has to change the name of their upcoming gaming app Blood Crystal: Tower Defense to something else.
How someone could trademark a genre, is beyond me. It is like trademarking the term "Sport Utility Vehicle" or "Power Tool."
Oh well, it is good that we found this out today, otherwise it would have delayed the release on our app by a good couple of weeks.