35 Numerical Prefixes

By Mark Nichol - 1 minute read

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This post lists prefixes of Greek and/or Latin provenance used in expressions of numerical relationships, with examples.

1. uni-: “one” (unicycle)
2. mono-: “one” (monogamy)
3–4. du-: “two” (duplicate); sometimes duo- (duopoly)
5–6. deuter-: “two” (deuterium); sometimes deutero- (deuterograph)
7. bi-: “two” (bicycle) or “twice” (biannual)
8. di-: “two” (dilemma)
9. tri-: “three” (triangle)
10. quadr-: “four” (quadrant)
11. tetra-: “four” (tetrahedron)
12–13. quin-: “five” (quintet); sometimes quinque- (quinquelateral)
14. penta-: “five” (pentathlon)
15. sex-: “six” (sextuplets)
16. hexa-: “six” (hexagram)
17. sept-: “seven” (septuagenarian)
18. hept-: “seven” (heptarchy)
19–20. oct-: “eight” (octennial); sometimes octo- (octopus)
21. nona-: “nine” (nonary)
22–23. nove-: “nine” (novennial); sometimes novem- (novemdecillion)
24. ennea-: “nine” (enneagram)
25–26. dec-: “ten” (decennial); sometimes decem- (decemvirate)
27. deca-: “ten” (decade)
28. cent-: “hundred” (centipede)
29–30. hect-: “hundred” (hectare); sometimes hecto- (hectoliter)
31–32. mill-: “thousand” (million); sometimes mille- (millennial)
33. kilo-: “thousand” (kilowatt)
34. chili-: “thousand” (chiliad)
35. myri-: “ten thousand” (myriad)

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15 Responses to “35 Numerical Prefixes”

  • D.A.W.

    In the ancient Roman calendar, March was the first month of the year. Some of the months took newer names from different sources, such as Julius Caesar and August Caesar, or more pedestrian sources. Hence, March, April, May, June, July, August, but then the older system prevailed:
    7th month, September,
    8th month, October,
    9th month, November,
    10th month, December.
    Next, the 11th month contained the end of autumn and the beginning of winter, so it was named for Janus, the god of beginnings and ends (the god with two faces).

  • D.A.W.

    Sorry, but the spellchecker changed “Augustus” into “August”.
    Also, “Quentin” was the fifth-born son (or child), and “Octavius” was the eighth-born son (or child).
    You did not complete the list of three important athletic events: the pentathlon (five), the heptathlon (seven), and the decathlon (ten). The decathlon is for men, and it consists of three running distances, one hurdling, three weight-throwing, and three jumping (including the pole vault).
    The heptathlon is for women, and it consists of one fewer run, one fewer weight-throwing, and one fewer jumping (no pole vault). Hence, it has four events on the 1st day and three events on the 2nd day, rather than five plus five, finishing with the grueling 1,500 meter run. The women finish up with 800 meters.

  • D.A.W.

    You have left out most of the common prefixes in the International System of units (the S.I.).
    pico = 10^-12, nano = 10^-9, micro = 10^-6, centi = 1/100, deci = 1/10; mega = 10^6 = 1,000,000; giga = 10^9; tera = 10^12.
    Many of these are important in communications engineering and in pharmaceuticals, yielding such units as these:
    picowatt, nanowatt, nanogram, microwatt, microgram, centimeter, deciliter, decibel, megawatt, megabyte, gigawatt, gigabyte, terawatt, terabyte.

  • D.A.W.

    The hectare is an area equal to a square of 100 meters by 100 meters. It comes in as useful in agriculture and related fields because one hectare is about 2.47 acres.

  • PAUL WILLIAM DIXON

    There are also:
    meth- (one) e.g. methanol
    sesqui- (one and a half): sesquioxide
    eth- (two) e.g. ethanol
    prop- (three) e.g. ´propane
    but- (four) e.g. butanoic acid
    dodeca- (twelve) e.g. dodecagon
    (e)icosa- (twenty) e.g. icosahedron

  • D.A.W.

    Mr. Dixon, those are very nice additions. Here they are, with some additional simple examples:
    meth – methane
    sesqui – (one and a half): sesquicentennial (150th anniversary)
    eth – ethane
    prop – propane
    but – butane
    dodeca – dodecahedron, the Platonic solid with 12 triangular sides
    icosa – icosahedron, the Platonic solid with 20 pentagonal sides
    It can be shown mathematically that there are only five Platonic solids that can exist in three dimensional space. The others are the tetrahedron, the cube, and the octahedron.
    It can also be shown that making such a figure with regular hexagon is impossible because the angles do not work out right.
    The exterior of a soccer ball is made of a mixture of regular pentagons and regular hexagons, arranged in a clever way.
    Four-dimensional space is unusual in that we can construct SIX Platonic solids. For higher-dimensional spaces, the number is always five or fewer.

  • D.A.W.

    “Sesquioxide” is an interesting word that I had not heard of before, concerning the ratio of 3:2. Figuring from the ratio, these are all sesquioxides: U2O3, (Pu2)O3, (Th2)(O3) – some common oxides of uranium, plutonium, and thorium.
    Also, for nearly all of the rare earth elements starting with lanthanum and cerium, the most common oxide is of the form (La2)O3.
    The chemist John Dalton figured out the “Law of Multiple Proportions”, and that explained that metals like iron and uranium would form multiple oxides, such as FeO, (Fe2)O3, and FeO2, and they all do: E.g. U2O3, UO2, and UO3.

  • D.A.W.

    chil·i·asm (kĭl′ē-ăz′əm):
    The doctrine stating that Jesus will reign on Earth for 1,000 years.
    There are many variations on this notion that you can find on the Internet.

  • D.A.W.

    The nucleus of ordinary water is one proton, and when orbited with an electron, this is called “protium”.
    The nucleus of deuterium is made of one proton plus one neutron, and it is called a “deuteron”. This is useful in nuclear physics.
    The nucleus of tritium is made of one proton plus two neutrons, and it is called a “triton”.
    The first pair of stable isotopes to be discovered were neon-20 (Ne-20) and neon-22 (Ne-22), which were found considerably earlier than deuterium was.
    Ne-20 has 10 protons and 10 neutrons, but Ne-22 has 10 protons and 12 neutrons. Stable Ne-21 does exist, but it is extraordinarily rare, and so it was not found at the same time as Ne-20 and Ne-22. All of the other isotopes of neon are very radioactive, and they do not count for very much.

  • D.A.W.

    Here is a prominent numerical prefix that has been left unmentioned so far: MULTI, such as in these words:
    multitude, multifarious, multivariate, multifactorial, multiprocessor, multilateral, multinational, multifactional, multistate, multiman, multilane, multiband.
    Just because a prefix does not refer to a specific number does not keep it from being numerical.
    There is also the probability of exaggeration:
    a millipede does not literally have 1,000 legs, just as a centipede does not literally have 100 legs. Also, the word “myriad” does not necessarily mean 10,000, but rather it means “a very large number”.
    For example: The European countries have a myriad of reasons for being grateful to the United States and Canada. (Beginning with the defeats of Kaiser Wilhelm II and Adolf Hitler, and continuing into the Marshall Plan.)
    We have multifactional warfare and genocide in Syria right now, and nobody cares how many factions are in “multi”.

  • D.A.W.

    Words for weapons, scientific instruments, military establishments, etc., that utilize numerical prefixes:
    binocular microscopes and telescopes, the trident, the quadrant, The Pentagon, the sextant, the octant, the multimeter in electrical work, the multispectral scanner,
    The Marine Corps (of several different countries) are fighting forces with a triad of capabilities: landbound, seaborne, and airborne. Then came along the Navy SEALs, in which each man has capabilities in all three realms, including expert marksmanship, scuba diving and swimming, and parachute jumping.

  • venqax

    But, to be clear, meth, eth, prop, and but are not numerical prefixes, per se. They are not derived from words for numbers. They are simply preservations of the original, pre-existing names for the compounds in question. there numerical properties not considered.

  • venqax

    their

  • D.A.W.

    multiannual, multiband, multiclimatic, multicomputer, multicount, multiday, multidimensional, multifaced, multifaceted, multifarious, multifactional, multifactorial, multifunction, multilane, multilateral, multiman, multinational, multiplane, multiply, multiport, multiprocessor, multiracial, multistate, multitude, multivariate, multivehicle, multiverse, multiwoman, multiyear.
    Being two-faced is bad enough, but “multifaced” is even worse.

  • Dale A. Wood

    Also referring to large multiples, often unspecified: “hyper”, as in
    hyperactive, hyperbaric (high pressure), hyperdense, hyperfine, hypermodern, hyperpotent, hyperreal, hypersonic, hypertonic.
    In aeronautics, “hypersonic” is usually taken as five times the speed of sound, or faster. For example, “The American X-15 was the first hypersonic aircraft.”
    Similar uses are found for “ultra” and “super”, such as in “superluminal”, which means “faster than the speed of light”.

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