Linux is trademarked
because of some "hijinx"...
"Initially, nobody registered it, but on August 15, 1994, [...] filed for the trademark Linux, and then demanded royalties from Linux distributors. In 1996, Torvalds and some affected organizations sued him to have the trademark assigned to Torvalds, and, in 1997, the case was settled." https://en.wikipedia.org/wiki/Linux#Copyright,_trademark_and...