Ubisoft has contacted the U.S. Patent and Trademark Office to stop EA trademarking the word "Ghost", according to a thread on NeoGAF.
The Assassin's Creed developer has filed a notice of opposition against EA's trademark application as it believes its own Ghost Recon trademark will "be damaged" as a result.
EA is looking to trademark the term due to it being the name of its in-house development studio, Ghost - the developer behind Need For Speed Rivals and the more recent reboot, Need For Speed.
Although the lawsuit has only just been raised, Ubisoft's opposition was actually filed on August 4, 2015.
In the filing the publisher cites a number reasons, including the length of time it's been using the Ghost Recon trademark and the fact both companies are looking to use the term in connection with video games, as reasons to dismiss EA's application.
EA has until March 9 to respond.