A simple example: "OK" (or "okay") is a distinct Americanism. So my characters in Green and the subsequent books never use the term, as the setting is a secondary world without America or a close analog of America. On the other hand, I am willing to use the term in the Mainspring books, because America exists there, albeit in a rather different form.
But what about words that are explicitly tied to other cultural aspects of our world? I'm not talking about deep etymology here, but obvious stuff. The specific example on my mind this morning is the term "Trojan points" to refer to the L4 and L5 points in a two-body system. They figure into the steampunk lost colony religious novella I'm mulling (and currently researching), but if you have a world with no Odyssey and no Iliad, and likewise no direct linguistic or cultural connection to the present, the word "Trojan" is a null. For that matter, the same problem pertains to "Lagrange", which is the "L" in "L4" and "L5".
In a broader sense, this applies to any term derived from a personal or place name, of course — "Machiavellian", for example, or "volt", and likely many other words besides.
I go back and forth on this all the time. On the one hand, I write in English. Regardless of the conceit of language within the story, my readers are reading in the same language, or a translation thereof. "Volt" is a normal English word, regardless of whether you've ever heard of Alessandro Volta. Likewise "Trojan." So if I work out some circumlocution, I'm only confusing the readers. Besides which, any circumlocution I attempt is quite possibly to have similar etymological issues of its own.
We don't see the buried etymologies so well, unless we're philologists. I suppose the problem exists at all levels.
How do you handle this as a writer? Do you even notice this as a reader? Or is this one of my private tics?