I'm writing a tech doc and this question bothers me, though I know it should be simple.

I know I should say "A pair of [Key, Value]", but when I have something like "A ____ of [Key, Value, Flag]", I'm just not sure if the proper word is triple, or something else.

Is triple often used as an adjective instead of a noun? Is there a better word?

  • 2
    'Triple' can be used as an adjective: triple crown in horse racing, triple score in a video game, a triple scoop for an ice cream cone. As a noun or adjective, triple is probably the best of all the examples (the others have more context restricted usage).
    – Mitch
    Commented Aug 29, 2011 at 13:42
  • 4
    another one, not mentioned yet is triplet(as a noun) Commented Aug 29, 2011 at 16:10
  • 2
    Yeah, I would say "triplet".
    – Hot Licks
    Commented Jan 25, 2016 at 19:28
  • 'Triplet' refers most frequently to siblings born simultaneously. This is a technical document. 'Trio' is better (and shorter if you're interested in saving space). From OED 2. A group or set of three: b. of things or animals; in quot. 1777 a stanza of three lines; in Cricket, three runs. Commented Jun 3, 2019 at 9:59
  • 1
    How about a threesome
    – Stu W
    Commented Feb 5, 2021 at 15:47

6 Answers 6


If you were not writing in a technical context, an option is the noun, trio:

  1. [countable + singular or plural verb]

a group of three people or things

A trio of English runners featured in the women's 1500 metres.

However, for technical contexts triple is perfectly fine. You can use triple as a noun, as the Merriam Webster dictionary indicates. Wiktionary indicates that one of the few uses of triple as a noun is:

(mathematics, computing) A sequence of three elements or 3-tuple.

For your case, I would recommend triple because trio sounds a bit more hoity-toity. Both would be accurate, but I think triple carries the right tone. (For example, there are Pythagorean triples but not Pythagorean trios).

  • 8
    In a computing context, 3-tuple is probably more usual. Mathematicians seem to prefer triple, as in your example. Commented Aug 29, 2011 at 11:35
  • Good point @Karl. Is it used in tech docs? I've only ever used it to talk about a program informally
    – user10893
    Commented Aug 29, 2011 at 11:38
  • Google NGrams doesn't seem to have heard of 3-tuples, but the use of the word 'tuple' in general has skyrocketed in the computer era (before which it was practically unheard of), so... Commented Aug 29, 2011 at 11:48
  • 1
    'Trio' is much more restricted in usage than triple. It is the common name for a piece of music for three instruments, but is also used for a group of three people
    – Mitch
    Commented Aug 29, 2011 at 13:53

A couple of related words are threesome and triad, both of which mean a group of three. In general, threesome is used for people and triad, for inanimate objects.

  • 4
    I'd use 'trio' as suggested above. 'Threesome' has sexual connotations, and 'triad' has Chinese mafia connotations. 'Trio' is nice and generic, perfect for a technical manual. Commented Jun 3, 2019 at 9:50


A set or succession of three similar things.

  • 'The reason why a triplet or quad of Aces is worth so few points is because they can be very easy to get.'
  • 'It constitutes a triplet, the first number representing the position, the second the wavelength and the third the transmission.'
  • 'DNA, RNA, and protein triplets or pairs were united on the basis of a high degree of similarity as detected by the appropriate blast algorithm or on the basis of annotation.'

(Oxford Dictionaries)

For some reason, nobody posted this as an answer yet even though Theta30 mentioned it in a comment in 2011.

  • Nobody posted this as an answer before you because triple is the logical increment of tuple; triplet is the logical increment of twin. In informatics, a key-value pair is called tuple or 2-tuple. Therefore, an ordered multiset of three elements such as key-value-flag would either be called 3-tuple or triple.
    – user33313
    Commented Jun 8, 2017 at 14:25

In exactly your technical context, the proper term is a "3‑tuple", also usable as just "tuple" in context. See Wikipedia. The term is common among mathematicians and functional programmers, and less so in the broader techie community, but still recognizable.

An added bonus is that you can have an "n‑tuple". Whenever you need one, a 5‑tuple or an 843‑tuple are just as fine. But then again, that "pair of [key, value]" is better expressed as a "2‑tuple of [key, value]" for the sake of consistency.

If you want a more layman-like term, I believe the good old "trio" would be appropriate.


Triple is also used as noun, but its meaning is different from the meaning of the adjective. Among others, the meanings of triple as noun reported by the NOAD are the following:

  • a thing that is three times as large as usual or is made up of three standard units or items
  • (triples) a sporting contest in which each side has three players
  • another term for trifecta

The OED reports also that triple as noun means "a thing consisting of three parts; a set of three items."

He pressed […] a triple of keys.—Joyce


In cards, after a pair you get a prial for 'three of a kind'. I know it from a card game called brag.

Most dictionaries, and indeed the brag Wikipedia page linked above, state that it's a corruption of pair royal, but until I looked it up to make sure at least one dictionary had it, I'd never heard of a pair royal.

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