Three
From Wikinfo
- For the year AD 3, see 3.
Three (3) is the natural number following two and preceding four.
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Properties of three
- Three is the second smallest prime number, and the only one divisible by 3, the next is five.
- Three is the second triangular number.
- Three is the first Fermat prime.
- Three is a Fibonacci number (And it is the third different one, too!).
- Fractions with 3 in the denominator have a single digit repeating sequences in their decimal expansions, (.000…, .333… or .666…)
- A natural number is divisible by three if and only if its decimal digit sum is divisible by 3.
- The base-3 numeral system is the ternary system.
Three-ness in human culture
Many human cultures have given the concept of three-ness symbolic meanings:
- The Holy Trinity in Christian doctrine (or trinity in general)
- The process of synthesis in Hegelian dialectic creates three-ness from two-ness
- The three Doshas (weaknesses) and their antidotes are the basis of Ayurvedic medicine in India
- The three Gunas underlie action, in the Vedic system of knowledge
- The Trimurti in Hindu tradition
- Three (三 pinyin san1) is considered a good number in Chinese culture because it sounds like the word "alive" (生 pinyin sheng1), compare to four
More references to groups of three
- 3-D
- Three-decker - a ship of three decks
- Three-spine stickleback - a type of fish
- Three-toed woodpecker
- Threepence - three-penny coin
- Threesome - trio or else
- Thrice - three times
- Triad - a group of three
- Trialogue - conversation among three
- Triangle - polygon with three sides
- Triangulation
- Triangulum and Triangulum Australe - constellations
- Triarchy - government of three
- Triassic Period - geologic time
- Triathlete - contestant in Triathlon
- Triathlon - contest in three sports
- Tribrach - metrical foot, in poetry
- Triceps - a muscle
- Triceratops - a dinosaur
- Trichotomy - division into three parts
- Trichroism - property of minerals such as tanzanite, andalusite and iolite
- Trichromatism - of three-color technology or perception
- Triclinium - a couch to three sides of table
- Tricolor - three-color flag, as in France, Romania, Moldova
- Tricorn - of three corners, e.g., a hat with "tricorned brim"
- Tricuspid - of three cusps
- Tricycle - (bicycle × 1½)
- Tridactyl - of three toes
- Trident - of three teeth or prongs
- Triennium - three-year time
- Trierarch - captain or manager of a trireme
- Trifid - cleft into three
- Trifocal - a lens (e.g., of eyeglasses) with three focal lengths
- Trifoliate - a leaf structure
- Triforium - a certain gallery in church
- Trifurcate - threeforked or threestemmed
- Trigeminus - trigeminal nerve
- Triglyph - an ornament
- Trigon - triangular harp
- Trigonometry - a branch of mathematics
- Trigram - I Ching thing
- Trigraph - three-letter combination
- Trihedron - afigure of three meeting planes
- Trihybrid - a kind of hybrid
- Trilateral - of three sides or parties
- Trilingual - able of or expressed in three languages
- Triliteral - a word or root of three letters
- Trilithon - prehistoric three-stone structure
- Trillion - 1012 (American) 1018 (British)
- Trilobate - of three lobes
- Trilobite - a marine arthropod
- Trilogy - three works on a theme under the same authorship
- Trio - three musicians or three actors
- Tripartition - division into three parts
- Tripod - a three-legged structure
- Trireme
- Triumvirate - government of three
- Trivium - grammar+logic+rhetoric ("three roads")
- Troika
Chemicals
Triacid, Triaminic, Triamcinolone, Triazine, Triazole, Tribromoethanol, Trichloroethylene, Trichlorfon, Trifluralin, Triglyceride, Triglycerophosphate, Triphosphopyridine nucleotide
Other references to three
- "In Memory of 3" - a phrase about NASCAR driver Dale Earnhardt
- No. 3 - 1997 Korean gangster comedy written and directed by Neung-han Song
- 3 - a rock band formed by Keith Emerson, Robert Berry and Carl Palmer
- Three Kingdoms
- Three Gorges
- Three-letter abbreviations and acronyms
- Three links
- Three of a kind - in poker
- Three Principles of the People
- Three Represents
- Three's Company - an American sitcom
- Three Years of Natural Disasters
See also: one, two, three, four, five, integer, list of numbers.
References
- Adapted from the Wikipedia article, "Three" http://en.wikipedia.org/wiki/Three, used under the GNU Free Documentation License
