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Learn the meaning, history, and usage of the word four, a number that is one more than three. See examples, related phrases, and nearby entries for four.
Learn about the history, mathematics, science, religion, and culture of 4, the natural number following 3 and preceding 5. Discover its divisors, factorization, arithmetic operations, geometric shapes, and more.
- four
- 4th, (fourth)
- 2²
- quaternary
Learn about the number four, its symbolism, and its role in number theory and cryptography. Find out how to express any positive integer as a product of primes and discover famous results and formulas related to primes.
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Four is the smallest composite number, its proper divisors being 1 and 2.Four is also a highly composite number. The next highly composite number is 6. Four is the second square number (a "square number" is an integer that can be written as the square of some other integer) and the second centered triangular number. (A "centered triangular number" ...
Astronomy
1. Four terrestrial (or rocky) planets in the Solar System: Mercury, Venus, Earth, Mars. 2. The orbits of four planets in the solar systemlie within that of the asteroid belt. 3. Four giant gas planets in the Solar system: Jupiter, Saturn, Uranus, Neptune. 4. Messier object M4, a magnitude 7.5 globular cluster in the constellation Scorpius. 5. The Saros number of the solar eclipse series that began on May 6, 2731 B.C.E. and ended on June 13, 1451 B.C.E.The duration of Saros series 4 was 1280....
Biology
1. Four is the number of the most common nucleotides in DNA and RNA, and therefore also the number of the most common bases in these nucleic acids: Adenine, guanine, cytosine, and thymine (uracilin RNA). 2. Many chordateshave four feet, legs or leglike appendages (Tetrapods). 3. The mammalian heartconsists of four chambers. 4. Many mammals (Carnivora, Ungulata) use four fingers for movement. 5. All insects with wings except flies have four wings. 6. There are four human bloodgroups (A, B, O,...
Chemistry
1. The element carbon (that is basis of life on Earth) has a normal valence of four. Thanks to its tetrahedral crystal bond structure diamond(one of the natural allotropes of carbon) is the hardest known naturally occurring material. 2. Four is also the valence of silicon, whose compounds form the majority of the mass of the Earth's crust. 3. Four is the atomic number of beryllium. 4. There are four basic states of matter: solid, liquid, gas, and plasma.
Four is the resin identification code used in recycling to identify low-density polyethylene.Usually, each item of furniturehas four legs. Examples include tables and chairs.Rectangles (with four angles and four sides) are widely used in making things because they have effective form and capability for close adjacency to each other. Examples include houses, rooms, tabl...The four color process (CMYK) is used for printing.In the Rich Text Format specification, language code 4 is for the Chinese language. Codes for regional variants of Chinese are congruent to 4 mod 256.Four is the number of bits in a nibble, equivalent to half a byte.Judaism
1. The Tetragrammaton (YHVH) is the four-letter name of God. 2. Four rivers in the Garden of Eden (Genesis 2:10–14): Pishon (perhaps the Jaxartes or Syr Darya), Gihon (perhaps the Oxus or Amu Darya), Hiddekel (Tigris), and P'rat (Euphrates) 3. The four Matriarchs of Judaism are Sarah, Rebeccah, Leah, and Rachel. 4. The Four Species (lulav, hadass, aravah and etrog) are taken as one of the mitzvot on the Jewish holiday of Sukkot. 5. The Four Cups of Wine to drink on the Jewish holiday of Passo...
Islam
1. The Four Archangels in Islam are: Jibraeel (Gabriel), Mikaeel (Michael), Izraeel (Azrael), and Israfil (Raphael)
Christianity
1. Four canonical Christian Gospels: Matthew, Mark, Luke, and John. 2. Four Horsemen of the Apocalypse ride in the Book of Revelation: War, famine, pestilence, and death.
The symbolic meanings of the number four are linked to those of the cross and the square. "Almost from prehistoric times, the number four was employed to signify what was solid, what could be touch...The Square of Opposition, in both its Aristotelian version and its Boolean version, consists of four forms: A ("All S is R"), I ("Some S is R"), E ("No S is R"), and O ("Some S is not R").Aristotle held that there are basically four causesin nature: The efficient cause, the matter, the end, and the form.In Western Music, common time is constructed of four beats.The number of completed, numbered symphonies by Johannes Brahms.The number of strings on a violin, viola, cello, double bass, cuatro, and ukulele, and the number of string pairs on a mandolin.Typically there are four movements in a classical symphony or string quartet.In the sportof cricket, a four is a specific type of scoring event, scoring four runs. Taking four wickets in four consecutive balls is typically referred to as a double hat trick (two consecutive,...
Four is the only number in the English languagefor which the number of letters in its name is equal to the number itself.Four (四, formal writing: 肆, pinyinsì) is considered an unlucky number in Chinese and Japanese cultures because it sounds like the word "death" (死, pinyin sǐ). Due to that, many numbered product lin...In the NATO phonetic alphabet, the digit 4 is called "fower."The number of characters in a canonical four-character idiom.Four rules in arithmetic: Addition, subtraction, multiplication, division.Classical Greek elements: Fire, air, water, earth.Four parts of a day: Morning, afternoon, evening, night.Learn about the number 4, its properties, history, and applications in mathematics, science, religion, and more. Find out why 4 is a special number in various fields and cultures.
4 days ago · Learn the meaning, pronunciation, and usage of the number 4 in English. Find synonyms, related words, idioms, and examples of 'four' in sentences and cricket.
Definitions of four. noun. the cardinal number that is the sum of three and one. synonyms: 4, IV, Little Joe, foursome, quadruplet, quartet, quatern, quaternary, quaternion, quaternity, tetrad. see more. adjective. being one more than three. synonyms: 4, iv. cardinal. being or denoting a numerical quantity but not order. noun.
Learn the meaning, pronunciation, and grammar of the number four in English. Find out how to use four in idioms, sports, and academic contexts with examples and pictures.
