Its like people using the word Football or Fire Department, would All be in trouble.
They certainly might be, if a single entity (like Microsoft) owned the word (like Windows).The quickest and cheapest way would be to release it, and see if you get sued. People who own a trademarked brand (like Pacman, FIFA, NFL, Apple, Microsoft) must defend their trademark vigoriously, or lose it forever, which is why you occasionally hear of completely absurb lawsuits, like the ones against Lindows and Mike Rowe Soft.
Thrust is a generic word/name
So is Windows. Just because something is generic, doesn't mean it can't be trademarked.