No such animal. There is no mechanism for obtaining exclusive rights in a string of characters, like Columbus claiming the new world for Queen Isabella.
By "trademarking", I assume you mean "registering a trademark in the US." But, that's the point.
A trademark isn't about establishing rights in some string of letters and symbols. It is about protecting the reputation and goodwill of someone who markets a product under a distinctive name, so that when consumers encounter that product so-marked in the marketplace, they have some idea of the quality of that product, whether it is the same thing that they've tried or seen before, etc..
When you look at this:
If you are an American beer drinker, and I asked you to choose from that selection, then it is highly likely that among "Budweiser", "Bud Light", "Stella Artois", "Heineken", "Miller Lite", and "Coors Light", you would have a definite idea of which of those you might pick, or whether you would keep looking for some shelves that look more like this:
...and you may have definite opinions about various of the brands there.
It can also depend on your beer drinking circumstances. If it's mid-summer and I'm having a cookout, then I'd probably grab some Corona or Red Stripe. I'm partial to Hoegaarden, but during Oktoberfest I tend to go for Paulaner, since that's the main beer on tap at my local German club party in the fall.
It's those sorts of associations... having Stella on tap in Belgium, or having associated various brands of beer with different beer drinking events, flavor preferences, etc., which are going to make me grab one or another of them if I am looking to pick up a six pack of beer. But I don't see any in that picture I haven't tried at one time or another.
That reputation based on association of consumer perception and the mark is the "goodwill" that has value to the producer and is what trademarks are about protecting.
Sure, "Corona" is a word that can be used for a lot of things, and the fact that it is a mark for beer does not prevent use of the word "corona" in such contexts as a coronavirus (so named because of the spiky "crown" appearance), astronomy or physics.
But there is not a mechanism for saying "this string of letters belongs to me and nobody else can use it" absent an awful lot of goodwill in a famous mark like, say, Coca-Cola, derived from massive global recognition by consumers.