This is something of a contradiction in terms.
A word is not "generic" in some free floating sense.
I'd like to see domainers start putting the word "for" after the word generic.
As in:
"Apple" is generic
FOR apples.
"Apple" is not generic
FOR computers.
Is the word "apple" generic? That's not even a well-formed question. Whether it is generic depends on what it is being used
FOR.
Many of the most well-known marks are what are called "arbitrary" marks. In other words it is a word which is "generic for" something, but not for the goods in question.
"TIDE" is generic for what the moon does to the water.
"TIDE" is not generic for laundry detergent. I believe it is the best selling brand of detergent in the US.
So, is the word "tide" generic? Again, it's a pointless malformed question in the first place.
Look around your home (or mom's basement or whatever)...
Just from where I'm sitting, I can see a "MONSTER" energy drink, a pair of "PUMA" athletic shoes, a "GIANT" bicycle, a bottle of "DAWN" dish detergent (I was de-greasing my chain), a bagel with "PHILADELPHIA" cream cheese on it, an "ASPIRE" vaporizer on my e-cig, a "MASTER" lock...
These words in quotes are all dictionary words. They are all generic
FOR something - a monster, a puma, a giant, the dawn, and so on.
But "generic" is not an intrinsic property of a word - whether a word is "generic" depends on how it is being used.
That is why, when you look at trademark registrations, they list the goods and services that the term in question is a trademark
FOR.
Yes, you can pick apples all day long and sell them, and nobody is going to sue you for calling them apples. But if you are selling computers, yeah, you're going to have a problem.
So I'm guessing the question in this thread is "If I have dog.com, should I get a trademark to protect my domain name?"
Well you can't have a trademark for "having a domain name". You can have a trademark for whatever goods and services for which the domain name functions as a trademark. If dog.com is going to, say, a PPC lander advertising things for dogs then, no, you aren't going to have a trademark and you aren't going to be able to register a trademark because "dog" is generic for things having to do with dogs.
But the flipside of that is that since "dog" is generic for dogs, then if you are USING the domain name for things having to do with dogs - such as a PPC lander with dog stuff on it - then nobody else is going to be able to successfully accuse you of abusing their trademark for "DOG". In other words, even if someone has a trademark for "DOG" as a brand of shoes, then if you are using the domain name dog.com for things having to with dogs, and not shoes, then you don't have a problem in the first place.