Let's say you have a sentence like

The circulatory system plays a dual role of carrying oxygen to the body's tissues and removing carbon dioxide to be expelled from the lungs.

However, what about

The circulatory system plays a _________ role of carrying oxygen to the body's tissues, removing carbon dioxide to be expelled from the lungs, carrying cellular waste products to the liver and kidneys for detoxification, and fighting disease through the production of antibodies.


9 Answers 9



Adj. having or involving three units or members - triple bypass heart surgery


Adj. having four units or members

And quintuple, sextuple, septuple, octuple. One could continue with nonuple but that's getting kind of silly.

(Citations from merriam-webster.com.)

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    Hooray! At last, somebody posts the actual answer, instead of random words that are somewhere between fanciful, high-falutin and wrong. Commented Mar 5, 2017 at 19:23
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    triple does not come after dual. comes after double.
    – user12103
    Commented Jun 28, 2018 at 14:52

You can use "threefold", "fourfold", and if allowing for even more options or composed by any more parts, I'd suggest "multiple" or "manifold".

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    I would say "multiple" for anything above two. You could number the portions if that makes for easier reading. Commented Mar 5, 2017 at 4:17
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    +1 for multiple. Personally I would go with triple for three, but switch to multiple for anything above that, to avoid scientific-sounding names such as quadruple.
    – Mr Lister
    Commented Mar 5, 2017 at 8:42
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    What's wrong with the simple "triple"? You wouldn't say "a twofold role", so why would you say "a threefold role"? Commented Mar 5, 2017 at 19:19
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    @DavidRicherby There's nothing wrong with "triple". It's just that there the OP's sentence presents the circulatory system as having four roles, not three, and "quadruple" would certainly sound terrible there, wouldn't it? I think "multiple" is a good choice that avoids using strange adjectives once a certain number has been exceeded.
    – Gustavson
    Commented Mar 5, 2017 at 23:49
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    "Quadruple" sounds just fine to me. Commented Mar 6, 2017 at 0:14

There seems to be no way of directly continuing the etymological pattern that formed 'dual' in English. Dual is derived from the latin dualis.

The equivalent number for for three in latin would be tres or tria. In English, we have the word 'trial'. We also have the prefix tri-, but that is not a word in and of itself.

In suspecting that trial would probably be the closest analog, I did come across 'paucal', which is listed as meaning:



  1. (grammar) pertaining to a language form referring to a few of something (three to around ten), as a small group of people; singular, dual, trial and plural.


3.(uncountable)(grammar) a language form referring to a few of something (three to around ten), as a small group of people; contrast singular, dual, trial and plural.

Excerpts from the Wikitionary entry of Paucal, licensed under the CC-SA-3.0 License.

It should be noted that I am not recommending 'paucal' as an alternative. It is a technical word with a restricted purpose that does not really match the desired definition, especially since it is less specific.

The reason I included the Wiktionary definitions of 'paucal', despite not recommending it, is that it suggests 'trial' would be the word to continue the pattern but again, if it were not for a couple of problems:

The linguistic word I found on Wiktionary suggests that a similar definition exists for trial, but that definition does not match either. I think this is actually more clearly demonstrated by the closest definition in the Randomhouse Kernerman Webster's College Dictionary, © 2010 definition of trial:

adj. 1. of or belonging to a grammatical category of number, as in some Papuan and Austronesian languages, used to indicate that a word denotes three persons or things.

More importantly, as I am sure you are all already well aware, 'trial' usually means something closer to "test" in English, and perhaps most especially the sort of test that requires adjudication in a court of law. I expect the word to be such a popularly and traditionally pervasive word that it is hard for me to endorse using the word to mean anything else, except perhaps by way of metaphor or metonymy.

As far as I can reliably discern, 'trial' does not even derive from tria, but the anglo-french triet which means something closer to try, as in an effort or attempt. Thus if you want a word which is in the same series as 'dual' that conveys the meaning you desire, I am currently of the opinion that a such word does not exist.

You may want to consider 'plural' as a possible alternative, but it is not as specific:

plural, adjective [Latin pluralis, from plus, pluris, more.]

  1. Containing more than one; consisting of two or more, or designating two or more; as a plural word.

The American Dictionary of the English Language by Noah Webster

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    @StuW Wikitionary lists the same definition as an adjective. However the point of this answer is not so much to suggest Paucal, as it is to corraborate the notion that the most likely word to be a part of the series does not exist. Saying no such word exists, is, as a matter of policy, a valid answer to a single word request and seems to apply to the titular question. I'll edit the answer momentarily.
    – Tonepoet
    Commented Mar 5, 2017 at 3:32
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    The Oxford dictionary gives a different definition of paucal as a technical term invented in the 1930s, used in describing the syntax of a language: "Designating a number or inflected form denoting more than two entities but fewer than the number denoted by the plural." (from Latin paucus, few). This seems irrelevant to the OP's question.
    – alephzero
    Commented Mar 5, 2017 at 4:40
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    Just to clarify, paucal is used in grammatical descriptions and is a part of the number system and may have exponence in the morphology or syntax of nouns, pronouns, and verbs. A singular pronoun in English is something like 'I', or 'she' whereas plural would be 'we' or 'they'. English only has singular and plural. Some languages have singular, dual and plural, wherein dual is 'we two', etc. Paucal is a category that some languages have which is more than dual/trial but not as many as plural.
    – Jangari
    Commented Mar 5, 2017 at 10:16
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    Why are your Random House and American Dictionary links so wacky??
    – Hot Licks
    Commented Mar 6, 2017 at 1:43
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    The Random House link goes to "The Free Dictionary", and the American Dictionary link goes to 1828.mshaffer.com, which appears to be some sort of religious dictionary.
    – Hot Licks
    Commented Mar 6, 2017 at 3:35

The trouble with multiple or multiplex is that they don't exclude duality.

A word that does exclude two-ness from a sense of (moderate) multiplicity is several or severalty.

However, you couldn't say something performed "a several role", you'd have to say "several roles". Or, at the risk of contrivance, "a severalty of roles..."


The word triune means three-in-one. It is most notably used in reference to the Holy Trinity, as

the triune Deity

referring to the Father, the Son, and the Holy Spirit.

However, it's use can be generalized to mean the same thing as dual, but for three.

  • Not sure why one would use this rather obscure word when the natural and obvious "triple" is, well, natural and obvious. If somebody wrote "triune" where "triple" could be used, I'd start looking at dictionaries, trying to figure out if they had some more nuance or more complex meaning in mind. Commented Mar 5, 2017 at 19:22
  • One definite problem with "triune" (besides the fact that spell checkers don't like it) is that it is very strongly associated with Christianity and "The Trinity". Very likely many readers would not understand that it could be used in a generic context.
    – Hot Licks
    Commented Mar 6, 2017 at 18:17

trichotomic. : belonging to, characterized by, or based upon a trichotomy

trichotomous : divided or dividing into three parts or into threes

tri·chot·o·my : a division into three categories.

Sources respectively: Merriam Webster, Merriam Webster, Google

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    It would improve the answer if you included the source of your definition. Commented Mar 5, 2020 at 7:40

Assuming you only had three roles and no more, perhaps the adjective triadic from triad would work.


The circulatory system plays a three-way role of carrying oxygen to the body's tissues...

This would be the most well-known way to phrase to sentence, it's very colloquial and not so scientific but nearly everyone will understand what you mean.

  • This doesn't feel right, to me. And isn't a "three-way role" actually three separate roles? Commented Mar 5, 2017 at 19:20

I was looking for the same thing, specifically for 3, and came across trinal. (For example, the aeroplane had dual controls.)

Re above suggestions: triple and three-fold have the connotation of identical instances or a multiplication of a single instance, which dual does not. (They also have the limitation of being related to double and twofold.) Three-way has connotations of some sort of physical object or direction, that I don't want either. Triadic might work but it is of Greek origin, whereas dual and trinal are from Latin.

Paucal, is not specific to three, but is a good alternative to multiple.

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