出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/12/01 02:39:05」(JST)
アルファ、アルファー、Alpha、Alfa、A、α
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Archaic local variants
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Alpha (uppercase Α, lowercase α; Greek: Άλφα Álpha) is the first letter of the Greek alphabet. In the system of Greek numerals it has a value of 1. It was derived from the Phoenician letter aleph . Letters that arose from alpha include the Latin A and the Cyrillic letter А.
In English, the noun "alpha" is used as a synonym for "beginning", or "first" (in a series), reflecting its Greek roots.[1]
In Ancient Greek, alpha was pronounced [a] when short and [aː] when long. Where there is ambiguity, long and short alpha are sometimes written with a macron and breve today: Ᾱᾱ, Ᾰᾰ.
In Modern Greek, vowel length has been lost, and all instances of alpha represent the short [a].
In the polytonic orthography of Greek, alpha, like other vowel letters, can occur with several diacritic marks: any of three accent symbols (ά, ὰ, ᾶ), and either of two breathing marks (ἁ, ἀ), as well as combinations of these. It can also combine with the iota subscript (ᾳ).
In the Attic-Ionic dialect of Ancient Greek, long alpha [aː] fronted to [ɛː] (eta). In Ionic, the shift took place in all positions. In Attic, the shift did not take place after epsilon, iota, and rho (ε, ι, ρ; e, i, r). In Doric and Aeolic, long alpha is preserved in all positions.[2]
Privative a is the Ancient Greek prefix ἀ- or ἀν- a-, an-, added to words to negate them. It originates from the Proto-Indo-European *n̥- (syllabic nasal) and is cognate with English un-.
Copulative a is the Greek prefix ἁ- or ἀ- ha-, a-. It comes from Proto-Indo-European *sm̥.
The letter alpha represents various concepts in physics and chemistry, including alpha radiation, angular acceleration, alpha particles, alpha carbon and strength of electromagnetic interaction (as Fine-structure constant). Alpha also stands for thermal expansion coefficient of a compound in physical chemistry. It is also commonly used in mathematics in algebraic solutions representing quantities such as angles. Furthermore, in mathematics, the letter alpha is used to denote the area underneath a normal curve in statistics to denote significance level[3] when proving null and alternative hypotheses. In zoology, it is used to name the dominant individual in a wolf or dog pack.
The proportionality operator "∝" (in Unicode: U+221D) is sometimes mistaken for alpha.
The uppercase letter alpha is not generally used as a symbol because it tends to be rendered identically to the uppercase Latin A.
In the International Phonetic Alphabet, a letter based on the lower case of alpha represents the open back unrounded vowel.
Alpha was derived from aleph, which in Phoenician means "ox".[4]
Plutarch, in Moralia,[5] presents a discussion on why the letter alpha stands first in the alphabet. Ammonius asks Plutarch what he, being a Boeotian, has to say for Cadmus, the Phoenician who reputedly settled in Thebes and introduced the alphabet to Greece, placing alpha first because it is the Phoenician name for ox — which, unlike Hesiod,[6] the Phoenicians considered not the second or third, but the first of all necessities. "Nothing at all," Plutarch replied. He then added that he would rather be assisted by Lamprias, his own grandfather, than by Dionysus' grandfather, i.e. Cadmus. For Lamprias had said that the first articulate sound made is "alpha", because it is very plain and simple — the air coming off the mouth does not require any motion of the tongue — and therefore this is the first sound that children make.
According to Plutarch's natural order of attribution of the vowels to the planets, alpha was connected with the Moon.
Alpha, both as a symbol and term, is used to refer to or describe a variety of things, including the first or most significant occurrence of something. The New Testament has God declaring himself to be the "Alpha and Omega, the beginning and the end, the first and the last." (Revelation 22:13, KJV, and see also 1:8).
The term "alpha" has been used to denote position in social hierarchy, examples being "alpha males" or pack leaders.
Character | Α | α | Ⲁ | ⲁ | ||||
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Unicode name | GREEK CAPITAL LETTER ALPHA | GREEK SMALL LETTER ALPHA | COPTIC CAPITAL LETTER ALFA | COPTIC SMALL LETTER ALFA | ||||
Encodings | decimal | hex | decimal | hex | decimal | hex | decimal | hex |
Unicode | 913 | U+0391 | 945 | U+03B1 | 11392 | U+2C80 | 11393 | U+2C81 |
UTF-8 | 206 145 | CE 91 | 206 177 | CE B1 | 226 178 128 | E2 B2 80 | 226 178 129 | E2 B2 81 |
Numeric character reference | Α | Α | α | α | Ⲁ | Ⲁ | ⲁ | ⲁ |
Named character reference | Α | α | ||||||
CP 437 | 224 | E0 | ||||||
DOS Greek | 128 | 80 | 152 | 98 | ||||
DOS Greek-2 | 164 | A4 | 214 | D6 | ||||
Windows 1253 | 193 | C1 | 225 | E1 | ||||
TeX | \alpha |
For accented Greek characters, see Greek diacritics: Computer encoding.
Character | ɑ | ɒ | ᶐ | ᵅ | ᶛ | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | LATIN SMALL LETTER ALPHA | LATIN SMALL LETTER TURNED ALPHA | LATIN SMALL LETTER ALPHA WITH RETROFLEX HOOK |
MODIFIER LETTER SMALL ALPHA |
MODIFIER LETTER SMALL TURNED ALPHA |
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Encodings | decimal | hex | decimal | hex | decimal | hex | decimal | hex | decimal | hex |
Unicode | 593 | U+0251 | 594 | U+0252 | 7568 | U+1D90 | 7493 | U+1D45 | 7579 | U+1D9B |
UTF-8 | 201 145 | C9 91 | 201 146 | C9 92 | 225 182 144 | E1 B6 90 | 225 181 133 | E1 B5 85 | 225 182 155 | E1 B6 9B |
Numeric character reference | ɑ | ɑ | ɒ | ɒ | ᶐ | ᶐ | ᵅ | ᵅ | ᶛ | ᶛ |
Character | ⍺ | ⍶ | 𝚨 | 𝛂 | 𝛢 | 𝛼 | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Unicode name | APL FUNCTIONAL SYMBOL ALPHA | APL FUNCTIONAL SYMBOL ALPHA UNDERBAR |
MATHEMATICAL BOLD CAPITAL ALPHA |
MATHEMATICAL BOLD SMALL ALPHA |
MATHEMATICAL ITALIC CAPITAL ALPHA |
MATHEMATICAL ITALIC SMALL ALPHA |
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Encodings | decimal | hex | decimal | hex | decimal | hex | decimal | hex | decimal | hex | decimal | hex |
Unicode | 9082 | U+237A | 9078 | U+2376 | 120488 | U+1D6A8 | 120514 | U+1D6C2 | 120546 | U+1D6E2 | 120572 | U+1D6FC |
UTF-8 | 226 141 186 | E2 8D BA | 226 141 182 | E2 8D B6 | 240 157 154 168 | F0 9D 9A A8 | 240 157 155 130 | F0 9D 9B 82 | 240 157 155 162 | F0 9D 9B A2 | 240 157 155 188 | F0 9D 9B BC |
UTF-16 | 9082 | 237A | 9078 | 2376 | 55349 57000 | D835 DEA8 | 55349 57026 | D835 DEC2 | 55349 57058 | D835 DEE2 | 55349 57084 | D835 DEFC |
Numeric character reference | ⍺ | ⍺ | ⍶ | ⍶ | 𝚨 | 𝚨 | 𝛂 | 𝛂 | 𝛢 | 𝛢 | 𝛼 | 𝛼 |
Character | 𝜜 | 𝜶 | 𝝖 | 𝝰 | 𝞐 | 𝞪 | ||||||
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Unicode name | MATHEMATICAL BOLD ITALIC CAPITAL ALPHA |
MATHEMATICAL BOLD ITALIC SMALL ALPHA |
MATHEMATICAL SANS-SERIF BOLD CAPITAL ALPHA |
MATHEMATICAL SANS-SERIF BOLD SMALL ALPHA |
MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL ALPHA |
MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL ALPHA |
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Encodings | decimal | hex | decimal | hex | decimal | hex | decimal | hex | decimal | hex | decimal | hex |
Unicode | 120604 | U+1D71C | 120630 | U+1D736 | 120662 | U+1D756 | 120688 | U+1D770 | 120720 | U+1D790 | 120746 | U+1D7AA |
UTF-8 | 240 157 156 156 | F0 9D 9C 9C | 240 157 156 182 | F0 9D 9C B6 | 240 157 157 150 | F0 9D 9D 96 | 240 157 157 176 | F0 9D 9D B0 | 240 157 158 144 | F0 9D 9E 90 | 240 157 158 170 | F0 9D 9E AA |
UTF-16 | 55349 57116 | D835 DF1C | 55349 57142 | D835 DF36 | 55349 57174 | D835 DF56 | 55349 57200 | D835 DF70 | 55349 57232 | D835 DF90 | 55349 57258 | D835 DFAA |
Numeric character reference | 𝜜 | 𝜜 | 𝜶 | 𝜶 | 𝝖 | 𝝖 | 𝝰 | 𝝰 | 𝞐 | 𝞐 | 𝞪 | 𝞪 |
Wikisource has the text of the 1897 Easton's Bible Dictionary article A (letter). |
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リンク元 | 「α」「アルファ」「alfa」 |
拡張検索 | 「alpha 2-macroglobulin receptor」「G12-G13 GTP-binding protein alpha subunit」「alpha-N-acetylgalactosaminidase」「cholestenone 5alpha-reductase」 |
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