Double, triple, quadruple, …

I recently needed a word for “multiply by 13” that was parallel to quadruple for “multiply by 4”, so I made up triskadekaduple by analogy with triskadecaphobia. That got me to wondering how you make words for multiples higher than four.

The best answer is probably “don’t.” Your chances of being understood drop sharply after quadruple. But despite the warning sign saying “hic sunt dracones” we forge ahead.

Double, triple, and quadruple are based on Latin names for numbers, so we should keep using Latin prefixes. Next would be quintuple, but I expect you would likely be understood if you said pentuple based on Greek penta-.

Next would be sextuple, septuple, and octuple. These terms are understandable, particularly in the context of multiple births: sextuplets, septuplets, and octuplets.

But now we hit a brick wall. The Latin prefix for nine is novem-, and it’s unlikely anyone would understand novemple or anything like that. The Greek prefix ennea– is no better. Enneauple? Enneaduple?

(The Latin prefix novem– is recognizable from November, which is the 11th month, so does that mean novem– stands for 11? No, November really is the ninth month, or at least it was when the year started in March.

The only example I can think of for a word starting with ennea– is the enneagram personality classification system.)

The prefixes after novem– are equally obscure. But if we jump to 13, some people will have heard of triskadecaphobia. This comes from tris kai deka (three and ten) from Greek. But I would only use triskadecaduple tongue-in-cheek.

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9 thoughts on “Double, triple, quadruple, …

  1. “Nonuplets” appears to be the accepted word for nine children in the same birth, but “dectuplet” is apparently preferred over “decuplet” for ten, so nonuple, dectuple and tredectuple would appear to be the right multiplier words for 9, 10 and 13.

    One alternative is “increase n-fold” where n is either a numeral or number name, e.g. 9-fold, ten-fold, thirteen-fold, etc.

  2. Interesting. Just a personal perspective here: reading this, when you got to quintuple and sextuple, my reaction was “those are just words”. Not very frequently used words, and not ones I go out of my way to use, but not anything that needed inventing. Past that I assume it’s been figured out at some point, but I agree they won’t be clear to most audiences.

    About 13: To me, “triskadectuple” sounds better. I have no idea whether this is more etymologically sound however.

  3. 7-tuple, 13-tuple it.

    I enjoy coining the occasional neologism[*], showing off to an unappreciative world how clever I am by assembling new dracones or chimeres (ha, pedantically Greek feminine plural there). Yet sometimes simple clarity lets us duck how thin our classical Latin and Greek can be when we only picked it all up through osmosis instead of study. Also, it saves the coiner the embarrassment of stitching up a chimera of a Latin root with a Greek one. Like, we say quintuple and not pentuple, pentagon and not quintagon.

    [*] Once I was studying the behavior of Bresnahan’s circle algorithm, working with integers, no antialiasing, black&white pixels. To draw a filled circle of radius r, nest outline circles of all radii from 0 to r. But if you’re drawing with XOR, it is necessary to draw each pixel exactly once — no gaps, obviously, but no overlaps either. What word describes unfilled circles that nest perfectly? After some etymological research, I called them “adjacerable annuli”. In fact: above, instead of “stitching up a chimera” I first wrote “adjacerating” the roots. Sometimes in straining for wit, one gets exactly halfway there.

  4. Not sure how reliable it is as a source, but wiktionary.org has an entry for “tredecuple” which defines it as meaning a tuple of thirteen thing. If it’s legitimate, then lagomoof seems to have been basically right.

  5. I looked in the Oxford English Dictionary and it does have an entry for “tredecuple”, however the only reference to its usage is by Sir Henry Billingsley in his first English version of Euclid’s Elements published in 1570, so I don’t think the OED are wrong when they call the word obsolete and rare! The details given are “Elements Geom. xvi. f. 453 To proue that an octohedron geuen, is tredecuple sesquialter to a trilater equilater pyramis inscribed in it”.

  6. I guess when you have a multiplicity of tuples we just use the word multi-ple?

    (my benighted contribution to the 1/2-wit category…)

  7. Simplex, duplex, triplex, et sic et semper.
    So: Latin, certainly not Greek, and the general rule for going from Latin to (Latinate) English is an extremely simple one: drop the ‘x’.
    I do not have enough Latin to know what, by regular formation, is the successor to octuplex.
    Meanwhile, fourfold, ninefold, thirteenfold, etc. are English — and they are literal cognates, which are the class of words in which the case for employing Latinate English is weakest.

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