• WordNet 3.6
    • n quaternity the cardinal number that is the sum of three and one
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Webster's Revised Unabridged Dictionary
    • Quaternity The number four.
    • Quaternity The union of four in one, as of four persons; -- analogous to the theological term trinity.
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Century Dictionary and Cyclopedia
    • n quaternity The state of being four; the condition of making up the number four.
    • n quaternity A group of four.
    • n quaternity [capitalized] Especially, the union of four persons in one godhead. Compare trinity, 3.
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Chambers's Twentieth Century Dictionary
    • Quaternity the state of being four, a group of four
    • ***


Webster's Revised Unabridged Dictionary
LL. quaternitas, fr. L. quaterni, four each: cf. F. quaternité,


In literature:

And yet this might not necessarily involve the conversion of the Trinity into a Quaternity.
"Tragic Sense Of Life" by Miguel de Unamuno
Another won 20,852 francs on the quaterne, 8, 16, 46, 64, in this very drawing.
"A Budget of Paradoxes, Volume I (of II)" by Augustus De Morgan
The Celestial King and his son form with God and Christ a Quaternity in Unity.
"Narrative of the Circumnavigation of the Globe by the Austrian Frigate Novara, Volume II" by Karl Ritter von Scherzer

In news:

Restoring Essential Hair Fiber Lipids with Quaternized 18-MEA.
Nalco, providing expertise for water, energy and air, recently announced that it will begin pilot plant production of quaternized dimethylaminoethyl acrylate for use in its industrial water treatment programs.
The acclaimed trombone ensemble Quaternity will visit Western Carolina University for a day of master classes followed by a public performance on April 23.

In science:

Q ≃ R4 taken with the This kernel defines a random field on the set of all real quatern background measure dµ (z ) = π−2e−|z |2 dm (z ) , where dm (z ) is the Lebesgue measure on Q.
On quaternion determinantal point fields
The first five Latin distributive numbers are singul-, bin-, tern-, quatern-, and quin- [], and these are apparently sources for the terms binary, ternary, quaternary, and quinary.