My question is, do you think the ansible needs any explanation within the story itself? We do live in the golden age of information, so it's not hard for someone to Google what the word means if they're curious, but I try not to assume too much on the part of my readers.
Ursula K. Le Guin coined the name “ansible” as a corruption of "answerable" for the communication devices in her science fiction. There is actually no end of similar concepts, whether borrowed from Le Guin or thought up originally to solve the problem. Star Trek uses “subspace communication”. Jack Williamson wrote about “rhodomagnetic waves”. Babylon 5 used “tachyon relays”. I worked on a similar concept before I’d even read Le Guin, that used “locus stones” for centers of communication in a fantasy story.
But to answer the question of describing a device—any technological/magical solution—you can go several ways. On the one hand, you can toss out a term, like ultrapowerosium, and if the reader can figure it out from context, then you're good to go. On the other hand, your world, your universe should exist. It should seem real. People don't say, "Hey, let's use the wireless, quantum entanglement ferret, otherwise called the w-Qec, to call your mom!" TV and movies tend to use this kind of exposition dialogue to explain to the audience what two (or more) characters either already know or should know. That doesn’t work in the really real world, unless one of the characters has been living under a rock, and has to squinch up their face and admit ignorance.
|Reach out and touch someone!|
Now, all that said, unlike TV/movies this is writing. Writers have a good deal of room for the character to consider the ultrapowerosium, and its impact within the narrative unverside, without resorting to awkward and shoehorned dialogue. A quick and dirty, or even slightly detailed explanation, can be had without slowing down the narrative. With one caveat—it must serve the story. Like Chekov’s Gun, you don’t necessarily want to get into the details of how ultrapowerosium was discovered, by whom, and so forth if it doesn’t serve the plot. It’s nice that you figured out how your magic system works on a I Ching mapping system, but if you’re going into vast detail now, it had better come back into play later.
With all that said, less is more. I used to worry and stress and maintain huge reams of information on descriptions and explanations of every kind for magic, technology, weaponry—everything. I was so worried that the readers wouldn't know what a character looked like, down to the eglets on their boots that the stories I was telling became vast deserts of exposition. Readers will build in their own version of your characters and the world that surrounds them without much assistance. A character doesn't have to be five-foot-two-and-a-half-inches flat footed, but five-foot-three-and-three-quarters when wearing her Zombie Ass Kicking boots. She can simply be short. She can be tall if everyone else is a Hobbit. It's all relative. As the author, you should be able to answer a three-deep question about anything in
|Mk IV locked and loaded!|
Who is your hero?
What kind of weapon does she carry?
A Mk IV handpistol in the 30-watt range.
What powers it?
Ultrapowerosium, of course.
It’s not important for readers to know that the Mk IV is made by Ultradyne Dyanmics, a competitor of Chuck Corp who is currently in a bitter rivalry for the Lazarianian military contracts. Unless that’s part of the story, those are just details you might keep in a file on your computer for later reference—usually your own. It’s good to have that for part seven of your thirteen volume opus, but in book one, the focus is probably going to be on your hero—and blowing the frell out of the Gorbags.
Those damn Gorbags.