I think the current case is interesting, because "GPT" is both a technical term as well as a term widely known in the general public by now. To illustrate with

I think the current case is interesting, because "GPT" is both a technical term as well as a term widely known in the general public by now. To illustrate with a fictionalised version: Suppose a few years from now, OpenFlyingCar Inc. becomes the first successful commercial vendor of flying cars. They archieved this using a revolutionary new design centered around a device they call "Gravity Inverter" or GI. (They'd probably also rush to patent this device, but let's assume it's still early days in the tech, so there are still a lot of easy, substantial improvements possible that a patent wouldn't cover) Competition is alarmed and soon there are several competing models on the market, from other automakers, each a variation of OpenFlyingCar's original design, each with its own improved reimplantation of a gravity inverter. OpenFlyingCar, having been the first however, their car is quickly established in the industry as the "reference design". Inside the industry, cars that copy the design are generally called "GI-based car" and "gravity inverter" becomes a term of art for any implementation of such a device, regardless of who made it. At the same time, OFC is still riding the initial wave of publicity and are heavily marketing their own car. Inside their marketing materials, the Gravity Inverter plays a prominent role - and of course they mean their own, original implementation by the term. So now suddenly, the term has two different meanings: Inside the industry, a "gravity inverter" is a term of art that refers to any device which supplies that specific functionality - whereas, the general public only knows about the "Gravity Inverter", which is a thing that OpenFlyingCar made and that is used in their cars to make them fly. So I wonder, would OpenFlyingCar under those circumstances be allowed to register "Gravity Inverter" as a trademark?