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{{Short description|First letter of the Greek alphabet}}
{{About|the Greek letter|the Latin letter|Latin alpha|the Cyrillic letter|A (Cyrillic)}}
{{Other uses}}
{{pp-semi-indef}}
{{Use dmy dates|date=November 2021}}
{{Greek Alphabet|letter=alpha}}

'''Alpha''' {{IPAc-en|'|æ|l|f|ə|audio=LL-Q1860 (eng)-Flame, not lame-Alpha.wav}} {{respell|ALF|ə}}<ref>{{OED|alpha}}</ref> (uppercase {{Script|Grek|'''Α'''}}, lowercase {{Script|Grek|'''α'''}}){{Efn|{{langx|grc|ἄλφα|álpha}}, or {{langx|el|άλφα|álfa}}}} is the first [[Letter (alphabet)|letter]] of the [[Greek alphabet]]. In the system of [[Greek numerals]], it has a value of one. Alpha is derived from the [[Phoenician alphabet|Phoenician]] letter ''[[Aleph#Origin|aleph]]'' {{angbr|𐤀}}, whose name comes from the [[West Semitic]] word for '[[ox]]'.<ref>{{cite dictionary | entry=aleph |last=Brookes | first=I. | dictionary=Chamber Concise Dictionary | publisher=Allied | year=2004 | isbn=978-81-86062-36-4 | url=https://books.google.com/books?id=iwWuY9tAVq8C | page=30 | access-date=15 November 2021 | archive-date=11 June 2022 | archive-url=https://web.archive.org/web/20220611085621/https://books.google.com/books?id=iwWuY9tAVq8C | url-status=live }}</ref> Letters that arose from alpha include the [[Latin script|Latin]] letter {{angbr|[[A]]}} and the [[Cyrillic]] letter {{angbr|[[A (Cyrillic)|А]]}}.

==Uses==

===Greek===
In [[Ancient Greek]], alpha was pronounced {{IPAblink|ä|a}} and could be either [[phoneme|phonemically]] long ([aː]) or short ([a]). Where there is ambiguity, long and short alpha are sometimes written with a [[Macron (diacritic)|macron]] and [[breve]] today: {{Lang|el|Ᾱᾱ, Ᾰᾰ|italic=no}}.
*{{Wikt-lang|grc|ὥρα|italic=no}} = {{Lang|grc|ὥρᾱ|italic=no}} ''{{Lang|grc-latn|hōrā}}'' {{IPA|el|hɔ́ːraː}} "a time"
*{{Wikt-lang|grc|γλῶσσα|italic=no}} = {{Lang|grc|γλῶσσᾰ|italic=no}} ''{{Lang|grc-latn|glôssa}}'' {{IPA|el|ɡlɔ̂ːssa}} "tongue"

In [[Modern Greek]], [[vowel length]] has been lost, and all instances of alpha simply represent the [[open front unrounded vowel]] {{IPA|el|a|IPA}}.

In the [[polytonic Greek|polytonic]] orthography of Greek, alpha, like other vowel letters, can occur with several [[diacritic]] marks: any of three accent symbols ({{lang|grc|ά, ὰ, ᾶ}}), and either of two breathing marks ({{lang|grc|ἁ, ἀ}}), as well as combinations of these. It can also combine with the [[iota subscript]] ({{lang|grc|ᾳ}}).

====Greek grammar====
In the [[Attic Greek|Attic]]–[[Ionic Greek|Ionic]] dialect of Ancient Greek, long alpha {{IPA|[aː]}} fronted to {{IPAblink|ɛː}} ([[eta]]). In Ionic, the shift took place in all positions. In Attic, the shift did not take place after [[epsilon]], [[iota]], and [[rho]] ({{Lang|grc|ε, ι, ρ|italic=no}}; {{Lang|grc-latn|e, i, r}}). In [[Doric Greek|Doric]] and [[Aeolic Greek|Aeolic]], long alpha is preserved in all positions.<ref>[[Herbert Weir Smyth]]. ''Greek grammar for colleges''. [http://www.ccel.org/s/smyth/grammar/html/smyth_1b_uni.htm#30 paragraph 30] {{Webarchive|url=https://web.archive.org/web/20110220092904/http://www.ccel.org/s/smyth/grammar/html/smyth_1b_uni.htm#30 |date=20 February 2011 }} and [http://www.ccel.org/s/smyth/grammar/html/smyth_1b_notes.htm#30D note] {{Webarchive|url=https://web.archive.org/web/20090313050255/http://www.ccel.org/s/smyth/grammar/html/smyth_1b_notes.htm#30D |date=13 March 2009 }}.</ref>
*Doric, Aeolic, Attic {{lang|grc|χώρᾱ}} ''{{Lang|grc-latn|chṓrā}}'' – Ionic {{lang|grc|χώρη}} ''{{Lang|grc-latn|chṓrē}}'', "country"
*Doric, Aeolic {{lang|grc|φᾱ&#769;μᾱ}} ''{{Lang|grc-latn|phā́mā}}'' – Attic, Ionic {{lang|grc|φήμη}} ''{{Lang|grc-latn|phḗmē}}'', "report"

[[Privative a]] is the Ancient Greek prefix {{Lang|grc|ἀ-|italic=no}} or {{Lang|grc|ἀν-|italic=no}} {{Lang|grc-latn|a-, an-}}, added to words to negate them. It originates from the [[Proto-Indo-European language|Proto-Indo-European]] {{lang|ine-x-proto|*n̥-}} ([[syllabic consonant|syllabic]] nasal) and is [[cognate]] with English ''un-''.

[[Copulative a]] is the Greek prefix {{Lang|el|ἁ-|italic=no}} or {{Lang|el|ἀ-|italic=no}} {{Lang|el-latn|ha-, a-}}. It comes from Proto-Indo-European {{lang|ine-x-proto|*sm&#805;}}.

===Mathematics and science===
{{main|Alpha (disambiguation)}}
The letter alpha represents various concepts in [[physics]] and [[chemistry]], including [[alpha radiation]], [[angular acceleration]],<ref>{{Citation |last=Elert |first=Glenn |title=Special Symbols |date=2023 |work=The Physics Hypertextbook|quote= '''α''', α rotational acceleration |url=https://physics.info/symbols/ |access-date=2025-02-01 |publisher=hypertextbook |language=en}}</ref> [[alpha particle]]s, [[alpha carbon]] and strength of [[electromagnetic interaction]] (as [[fine-structure constant]]).<ref>{{Cite web |title=fine-structure constant |url=https://physics.nist.gov/cgi-bin/cuu/Value?eqalph%7Csearch_for=fine |access-date=2025-02-10 |website=physics.nist.gov}}</ref> Alpha also stands for [[thermal expansion coefficient]] of a [[Chemical compound|compound]] in [[physical chemistry]]. In [[ethology]], it is used to name the [[Alpha (ethology)|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 astronomy, α is often used to designate the brightest star in a constellation.<ref>{{Cite book |last=Rabinowitz |first=Harold |title=The manual of scientific style: a guide for authors, editors, and researchers |last2=Vogel |first2=Suzanne |date=2009 |publisher=Elsevier/Academic Press |isbn=978-0-12-373980-3 |edition=1st |location=Amsterdam Burlington, MA |pages=363 |quote=The primary designation system for bright stars, called Bayer designations… The Greek letters are assigned in order (α,β, γ,δ  etc.) according to brightness.}}</ref>

In [[mathematics]], the letter alpha is used to denote the area underneath a [[Normal distribution|normal curve]] in [[statistics]] to denote [[statistical significance|significance level]]<ref>{{cite web|url=http://www.une.edu.au/WebStat/unit_materials/c5_inferential_statistics/what_alpha_level.html |work=Research Methods and Statistics PESS202 Lecture and Commentary Notes |title=Chapter 5: Analysing the Data Part II : Inferential Statistics |url-status=dead |archive-url=https://web.archive.org/web/20110822143239/http://www.une.edu.au/WebStat/unit_materials/c5_inferential_statistics/what_alpha_level.html |archive-date=22 August 2011 }}</ref> when proving [[null hypotheses|null]] and [[Alternative hypothesis|alternative hypotheses]]. It is also commonly used in [[algebra|algebraic solutions]] representing quantities such as angles. In [[mathematical logic]], α is sometimes used as a placeholder for [[ordinal number]]s. It is used for [[Stoneham number|Stoneham numbers]].<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Stoneham Number |url=https://mathworld.wolfram.com/StonehamNumber.html |access-date=2025-01-31 |website=mathworld.wolfram.com |language=en}}</ref>

Most occurrences of alpha in science are the lowercase alpha. The uppercase letter alpha is not generally used as a symbol because it tends to be rendered identically to the uppercase [[A|Latin A]].

The proportionality operator "[[∝]]" (in [[Unicode]]: U+221D) is sometimes mistaken for alpha.

===International Phonetic Alphabet===
In the [[International Phonetic Alphabet]], the letter ɑ, which looks similar to the lower-case alpha, represents the [[open back unrounded vowel]].

==History and symbolism==
{{More citations needed section|date=June 2021}}
{{further|History of the Greek alphabet}}

===Origin===
The [[Phoenician alphabet]] was adopted for Greek in the early 8th century BC, perhaps in [[Euboea]].<ref>The date of the earliest inscribed objects; A.W. Johnston, "The alphabet", in N. Stampolidis and V. Karageorghis, eds, ''Sea Routes from Sidon to Huelva: Interconnections in the Mediterranean'' 2003:263-76, summarizes the present scholarship on the dating.</ref> 
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 ''[[Aleph (letter)|ʼāleph]]'', the Phoenician letter representing the [[Glottal stop (letter)|glottal stop]] {{IPA|[ʔ]}},
was adopted as representing the vowel {{IPA|[a]}}; similarly, ''[[He (letter)|hē]]'' {{IPA|[h]}} and ''[[Ayin|ʽayin]]'' {{IPA|[ʕ]}} are Phoenician consonants that became Greek vowels, [[epsilon]] {{IPA|[e]}} and [[omicron]] {{IPA|[o]}}, respectively.

===Plutarch===
[[Plutarch]], in ''[[Moralia]]'',<ref>Symposiacs, Book IX, questions II & III [http://etext.library.adelaide.edu.au/p/plutarch/symposiacs/chapter9.html#section91 On-line text] {{Webarchive|url=https://web.archive.org/web/20081013230602/http://etext.library.adelaide.edu.au/p/plutarch/symposiacs/chapter9.html#section91 |date=13 October 2008 }} at Adelaide library</ref> presents a discussion on why the letter alpha stands first in the alphabet. Ammonius asks Plutarch what he, being a [[Boeotia]]n, has to say for [[Cadmus]], the [[Phoenicia]]n who reputedly settled in [[Thebes (Greece)|Thebes]] and introduced the alphabet to Greece, placing ''alpha'' first because it is the Phoenician name for [[ox]]—which, unlike [[Hesiod]],<ref>Hesiod, in ''[[Works and Days]]'' (see on [https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.01.0132:card=405 Perseus Project] {{Webarchive|url=https://web.archive.org/web/20210117133713/http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0132%3Acard%3D405 |date=17 January 2021 }}), advises the early Greek farmers, "First of all, get a house, then a woman and third, an ox for the plough."</ref> 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 [[vowel]]s to the [[planet]]s, alpha was connected with the [[Moon]].

===Alpha and Omega===
{{main|Alpha and Omega}}
[[Image: Königsberg Marienkirche - Fenster 1a AlphaOmega.jpg|right|thumb|Stained glass featuring Alpha and Omega in the {{ill|Marienkirche (Königsberg in Bayern)|de|lt=Königsberg in Bayern Marienkirche}}]]

As the first letter of the alphabet, Alpha as a [[Greek numeral]] came to represent the number [[1 (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.
 
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 [[Revelation 1:8|1:8]]).

Consequently, the term "alpha" has also come to be used to denote "primary" position in social hierarchy, examples being the concept of dominant [[Alpha (ethology)|"alpha"]] members in groups of animals.

==Unicode==
All code points with {{sc|ALPHA}} or {{sc|ALFA}}<ref>{{cite web|title=Character Encodings|url=http://www.kreativekorp.com/charset/|access-date=14 January 2013|archive-date=1 August 2019|archive-url=https://web.archive.org/web/20190801153209/http://www.kreativekorp.com/charset/|url-status=live}}</ref> but without {{sc|WITH}} (for accented Greek characters, see [[Greek diacritics#Computer encoding|Greek diacritics: Computer encoding]]):

* {{unichar|0251|html=}}
* {{unichar|0252|html=}}
* {{unichar|0386|html=}}
* {{unichar|0391|html=}}
* {{unichar|03AC|html=}}
* {{unichar|03B1|html=}}
* {{unichar|1D45|html=}}
* {{unichar|1D90|html=}}
* {{unichar|1D9B|html=}}
* {{unichar|1DE7|cwith=◌}}
* {{unichar|2376|html=}}
* {{unichar|237A|html=}}
* {{unichar|2C6D|html=}}
* {{unichar|2C70|html=}}
* {{unichar|2C80|html=}}
* {{unichar|2C81|html=}}
* {{unichar|AB30|html=}}
* {{unichar|AB64|html=}}
* {{unichar|1D6A8|html=}}{{efn|The {{sc|mathematical}} symbols are only to be used in math. Stylized Greek text should be encoded using normal Greek letters, with markup and formatting to indicate text style.}}
* {{unichar|1D6C2|html=}}
* {{unichar|1D6E2|html=}}
* {{unichar|1D6FC|html=}}
* {{unichar|1D71C|html=}}
* {{unichar|1D736|html=}}
* {{unichar|1D756|html=}}
* {{unichar|1D770|html=}}
* {{unichar|1D790|html=}}
* {{unichar|1D7AA|html=}}

==Notes==
{{Notelist}}

==References==
{{Wiktionary|Α|α}}
{{EBD poster|A (letter)}}
{{reflist}}

[[Category:Greek letters]]
[[Category:Vowel letters]]