Alpha  (uppercase ?, lowercase ?; Ancient Greek: ?, álpha, modern pronunciation álfa) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter aleph , which is the West Semitic word for "ox". Letters that arose from alpha include the Latin letter A and the Cyrillic letter ?.
In Ancient Greek, alpha was pronounced and could be either phonemically long ([a:]) or short ([a]). Where there is ambiguity, long and short alpha are sometimes written with a macron and breve today?, .
In the polytonic orthography of Greek, alpha, like other vowel letters, can occur with several diacritic marks: any of three accent symbols (?, ?, ?), and either of two breathing marks (?, ?), as well as combinations of these. It can also combine with the iota subscript (?).
In the Attic-Ionic dialect of Ancient Greek, long alpha [a:] fronted to (eta). In Ionic, the shift took place in all positions. In Attic, the shift did not take place after epsilon, iota, and rho (?, ?, ?; e, i, r). In Doric and Aeolic, long alpha is preserved in all positions.
Copulative a is the Greek prefix ?- or ?- 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 when proving null and alternative hypotheses. In ethology, it is used to name the dominant individual in a group of animals. In aerodynamics, the letter is used as a symbol for the angle of attack of an aircraft and the word "alpha" is used as a synonym for this property. In mathematical logic, ? is sometimes used as a placeholder for ordinal numbers.
The uppercase letter alpha is not generally used as a symbol because it tends to be rendered identically to the uppercase Latin A.
The Phoenician alphabet was adopted for Greek in the early 8th century BC, perhaps in Euboea. The majority of the letters of the Phoenician alphabet were adopted into Greek with much the same sounds as they had had in Phoenician, but '?leph, the Phoenician letter representing the glottal stop [?], was adopted as representing the vowel [a]; similarly, h? [h] and ?ayin [?] are Phoenician consonants that became Greek vowels, epsilon [e] and omicron [o], respectively.
Plutarch, in Moralia, 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, 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.
As the first letter of the alphabet, Alpha as a Greek numeral came to represent the number 1. Therefore, Alpha, both as a symbol and term, is used to refer to the "first", or "primary", or "principal" (most significant) occurrence or status of a thing.
Consequently, the term "alpha" has also come to be used to denote "primary" position in social hierarchy, examples being "alpha males" or pack leaders.
|Unicode name||GREEK CAPITAL LETTER ALPHA||GREEK SMALL LETTER ALPHA||COPTIC CAPITAL LETTER ALFA||COPTIC SMALL LETTER ALFA|
|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
|Named character reference||Α||α|
For accented Greek characters, see Greek diacritics: Computer encoding.
|Unicode name||LATIN SMALL LETTER ALPHA||LATIN SMALL LETTER TURNED ALPHA||LATIN SMALL LETTER ALPHA
WITH RETROFLEX HOOK
SMALL TURNED ALPHA
|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
|Unicode name||APL FUNCTIONAL SYMBOL ALPHA||APL FUNCTIONAL SYMBOL
|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||⍺
|Unicode name||MATHEMATICAL BOLD ITALIC
|MATHEMATICAL BOLD ITALIC
BOLD CAPITAL ALPHA
BOLD SMALL ALPHA
BOLD ITALIC CAPITAL ALPHA
BOLD ITALIC SMALL ALPHA
|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