I was taken aback while reading ”Bringing Mecca to the British Museum,” by the excellent writer Malise Ruthven, to see a sentence beginning “It includes the ritual circumambulation of the Ka‘ba, the cubular building that stands at the center of the Grand Mosque in Mecca...” Cubular?  Surely some sort of mistake, though not a simple typo.  It’s not in either the OED or Webster’s Third.  But when I plug it into Google Books, I get this, from p. 394 of the Official Gazette of the United States Patent Office for Dec. 8, 1903:

There are a number of hits for it over the years (1930, 1948, etc.); I especially liked this sentence from Jack Kerouac’s novel Doctor Sax: Faust Part Three, written in 1952 and first published in 1959, though Google Books dates it from 1987: “It hung in great black velvet folds in the cubular shadows of the high wall yard.”

What I’m wondering is whether it’s a rare but existing word that bubbles into print only every once in a great while, or an occasional mistake (or invention) by people who can’t come up with the word “cubic” when they need it (or dislike the word)?

FWIW, according to the Google Keyword tool, this exact word averages 110 searches a month globally. Even in “broad” searches (in this case that would mean the word used with other words) gets 480 searches a month. For comparison, the single word “cubic” gets 33K global searches a month and in “broad” searching gets 3 million+ searches. A test with the deliberate misspelling of “cubilar” gets zero searches a month.

Cubular is a “real” word as far as Google is concerned. You could buy ads centered around it.

It’s also a “Game of Strategy”.

I suppose the thinking goes, that if tube can become tubular, surely cube can become cubular.

Yes, that’s presumably the model, but it seems odd to me that anyone would use it in other than a jocular fashion when the normal adjective “cubic” is so well established.

From:  http://www.urbandictionary.com/define.php?term=Cubular

1. Cubular
A modern adjective describing an object possessing the shape of a cube. Also, a popular extension of the same naming convention of triangle, which has the adjective of triangular.
2. Cubular
Like circular, but for cubes
the building has a cubular structure
3. Cubular
August 28, 2005 Urban Word of the Day
Cubular describes anything which is “cool” in a “business-geek” office-context. Often used ironically. This is a term derived from “cubicle” and the surf-slang “tubular.”
The latest Blackberry; a new flat-panel display; highly effective CRM software; an entertaining web site; the latest designer cubicle-space or office furniture: all these things are “cubular.”