Usually, when I can’t remember a word, the problem presents itself like a crossword clue: I know it rhymes with “emancipation,” starts with a C, and means “big fire,” but I can’t come up with the word “conflagration.” This kind of brain lapse, in which a person can’t dredge up a desired word but may remember some of its personality, is called the tip-of-the-tongue phenomenon.

A few weeks ago, my brain wouldn’t bring me a word that I wanted. I was writing an essay about infinity, and I needed to say “a space of infinite size.” I sat at my desk staring at a half-filled Word page, aggressively tapping out ASDFASDF and hoping that the mystery term, whose first letter I could not remember to save my life or my deadline, would move from the tip of my tongue onto my vocal cords. If the word “forever” means “an infinite amount of time,” the spatial analog must also exist, I reasoned.

I turned to Facebook for help. Boundlessness? suggested scientists and a teacher. Endlessness? said a writer. But both are more about the lack of bounds and ends than about the space itself, and endlessness isn’t space-specific.

Infinity itself can have spatial connotations, and a geometric plane is infinite in two dimensions, countered some engineers. But while two dimensions are great, three or four are better. And besides, “infinity” shouldn’t have to do double-duty of meaning itself and also “infinite space.”

One friend directed me to a subreddit called WTW (What’s The Word?), but the fast-acting users gave the same suggestions as my Facebook friends. After a few hours, the moderator asked me to mark my query as “resolved” if I was satisfied with an answer. I wasn’t, but I’m afraid of moderators, so I lied.

I flipped through a book I have called “There’s a Word for That,” about ultra-specific terms that exist in non-English languages. Nothing. Finally, I concluded that the word for “a space of infinite size” wasn’t on the tip of my tongue because it doesn’t exist.

“Can we call it ‘the everspace’?” read a Facebook comment from, of course, an editor.

* * *

“Forever” has always been conceivable, if not concrete, because time ticks relentlessly onward. The sun rises and sets. Seasons come and go. The world gives no indication that it won’t continue forever. But the physical spaces we encounter tell us the opposite: They all have edges, boundaries, sizes. How often do infinite spaces, which we never have to deal with, come up in conversation? Pretty much never, unless you’re having coffee with cosmologists.

But cosmologists in the 20th century did discover, for the first time, that such infinite spaces might exist. And not just one, but a Sears Catalog of potential ones. Our own space—the universe—might be infinite. The latest results from instruments like the Planck Telescope, suggest that dark energy—the repulsive, gravity-opposing force—will push the universe to expand faster and faster, making it grow always larger, forever. On top of that, as scientists have learned more about the first moments after the Big Bang, many have come to believe we live in a multiverse. In this view, our universe is one of many—perhaps infinity—other universes, each with its own special-snowflake characteristics. Some of these surely expand like ours, and some of those will expand forever. But even without the expansion and those unseen other cosmos, humans can conceive of a universe without geographical end. Looking out into that dark 3-Kelvin vacuum, it’s almost harder to imagine that it doesn’t extend forever.

In fact, that conception led the Greeks to first write about infinity. They even came up with a word for it: “apeiron”: a- meaning “without” and -peirar meaning “end” or “limit.” They created the term because they noticed three things: Space doesn’t seem to have an edge. Time keeps going no matter what. Time and space can be subdivided into tiny, tiny, tiny chunks, but no matter how small the chunks, they could always be smaller.

The Greeks were on to something. But before they had a chance to figure out the multiverse, their civilization fell, and Arabic scholars preserved and advanced their math. These Arabic mathematicians were experts at manipulating numbers that go on forever—including irrational numbers, like pi. The philosophy of that endlessness, though, they left alone.

In the 16th century, Giordano Bruno brought back the loftier, fuzzier version of infinity. Long before NASA launched the Kepler Space Telescope, Bruno believed in an infinite number of worlds. And like some of today’s cosmologists, he also believed in an infinitely sized universe. This line of thought went up in flames when Bruno was burned at the stake (not just for his numerical madness) in 1600.

In the next century, Oxford-man John Wallis brought infinity back down to Earth and created the symbol {\infty}, which he coined in his surely riveting Treatise on the Conic Sections. In this tome, he wrote about the number of parallel lines or parallelograms that combine to make up a geometric plane. Each line, he wrote, would “be an infinitely small part 1/{\infty} of the whole altitude, and let the symbol {\infty} denote infinity.”

It was around this time that the word for infinite time—forever—came into use as an adverb. Example sentence: “Writing Treatise on the Conic Sections is taking forever.”

In the 18th century, Immanuel Kant thought about {\infty} less mathematically. He believed that everything—from your duvet cover to your best friend—has two forms: the noumenon and the phenomenon. The noumenon is also called the thing-in-itself—all of the aspects of your duvet cover and its essential duvet cover-ness, independent of your perception of it. The phenomenon is the way you as a pathetic human perceive it—your vastly oversimplified conception of your best friend. The universe may be infinite in both the sense of time and of space but that infinitude is only noumenal. Our perception—the phenomenon—can never actually encompass infinity, because we live for a handful of decades and interact only with measurable distances.

Mathematician Georg Cantor may, in the 1800s, also have contemplated the incomprehensibility of infinity, but he didn’t run from it. Instead, he experimented with it, inventing a whole field of math called set theory. Cantor’s biggest mind-blower was this: The set of natural numbers—1, 2, 3—is infinite. And the set of real numbers—1.11111111, 1.11111112, 1.11111113—is also infinite. But the latter infinity is bigger than the former one. It would take you forever to count both infinities, but one forever would be longer than the other. Around Cantor’s time, people began to use “forever” as a noun: It became a thing.

Now that scientists think the universe might be infinite, or that it might be embedded in an infinite multiverse, it’s time to make everspaces, like forevers, a thing. Then, maybe we’ll talk about them more, and better. New words and novel usages, after all, pop up to fill a void, to bridge our experience and our expression. “Quark,” for example, was coined because physicists didn’t want to keep writing “fundamental particle that, when combined with other fundamental particles, forms hadrons.”

Pythagoras first used the word “kosmos”—meaning “an ordered and harmonious system”—to talk about the character of the universe. To the Greeks, this word also meant “adornment” (specifically, it seems, of women’s appearances). But it wasn’t until the mid-nineteenth century that Alexander von Humboldt popularized the modern use of this word, which became the English “cosmos,” with his eponymous book. “The principal impulse by which I was directed was the earnest endeavor to comprehend the phenomena of physical objects in their general connection,” he wrote, “and to represent nature as one great whole, moved and animated by internal forces.”

He suggested that the physical laws we observe apply everywhere, on Earth as it is in heaven, even the parts of the heavens too far away to see. He chose the title Kosmos because bound within that term were both the Greek ideas about the universe—that it was ordered and law-abiding—and the secondary connotation of adornment. The adornment, he said, was our human interpretation of the laws and order. In this book, Humboldt also linked Earth to the space around it: It was all, together, kosmos.

Kosmos became cosmos became what we mean when we say “cosmos” today: everything (of which we and Earth are a part) and our attempts to make sense of that. In two beats, all of a sudden, a person could could convey all of that meaning. And the more they did, the more the cosmos seeped into the cave of our consciousness.

Even if we can never truly get what an infinite space is, we should give ourselves the linguistic tools to talk about it more, and better. If we had a word that cupped the concept in a few syllables, it could spill into our minds, little by little, until maybe one day we would get it. “Everspace”: a space that goes on forever. Try it out. See how it sounds.