[apical_dendrite]

plenty of words and phrases originate from fiction

quixotic, scrooge, shangri-la, Uncle Tom, gargantuan, kafkaesque, blurb, milquetoast

and words like cyberspace were first used in fiction

once real people use them, they stop being fictional words

[fl4regun]

The word was "Brobdingnagian", which apparently means "giant", from the book, Brobdingnag, published in the 1700s. I know all of the words you listed, even if I don't know t he books they came from, on the other hand, I've never heard anyone use "Brobdingnagian" and I've never heard of the book it came from either.

[krustyburger]

Kafkaesque doesn’t originate directly from fiction like your other examples any more than a word like Dickensian does.

[triceratops]

Well it does and it doesn't. It wouldn't be a word if Franz Kafka hadn't written any fiction. Same for Dickensian.