al·pha | \ˈal-fə \

Definition of alpha 

(Entry 1 of 2)

1 : the 1st letter of the Greek alphabet — see Alphabet Table

2 : something that is first : beginning

5 : the first version of a product (such as a computer program) that is being developed and tested usually used before another noun alpha versionsalpha testing also : a stage of product development in which alpha prototypes are released a product that is available in alpha — compare beta



Definition of alpha (Entry 2 of 2)

1 : closest in the structure of an organic molecule to a particular group or atom symbol α α-substitution

2 : socially dominant especially in a group of animals an alpha male

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Examples of alpha in a Sentence


money is not the alpha and omega—the beginning and end—of life's purpose

Recent Examples on the Web: Noun

The book tells the story of the alpha female, O-Six, who became a favorite of wolf watchers and conservationists. The Editors, Outside Online, "Beyond Books Club: The 'American Wolf' Author Podcast," 9 July 2018 In the 1950s, an IBM engineer named Arthur Samuel created a checkers-playing program that learned in part by matching an alpha side against a beta side. Joshua Sokol, The Atlantic, "AI Keeps Mastering Games, But Can It Win in the Real World?," 27 Feb. 2018 Essentially the meat allergy is an allergy to the alpha-gal carbohydrate that's found in cows, pigs, sheep and other non-primates, but not humans. CBS News, "Red meat allergy transmitted by lone star ticks on the rise," 5 July 2018 Eskhanov said the app was in a testing phase when Kadyrov was banned from Instagram in December, but quickly accelerated to alpha once he had joined. Amie Ferris-rotman, Washington Post, "Defying U.S. sanctions, Chechnya has created its own version of Instagram. Its strongman leader is a fan.," 29 May 2018 The two alpha males going at it, matching profiles of intimidation, matching nerves of major steel. Tara Sullivan,, "Some head-to-head dream matchups we wish we could see," 12 July 2018 Find the Right Formula Many of the latest exfoliating toners contain a blend of alpha and beta hydroxy acids suited to different skin types, says Mattioli. New York Times, "How to Exfoliate, Without Damaging Your Skin," 29 May 2018 Budenholzer started working on the relationship immediately, meeting with Antetokounmpo and Khris Middleton, the Bucks’ alpha and beta dogs, over breakfast. Gary D'amato, Milwaukee Journal Sentinel, "D'Amato: This Bud's for you, Milwaukee Bucks fans," 21 May 2018 Of course the frisker was measuring gamma waves in addition to alpha and beta particles; all these people presumably cared about was the particles, which could continue to do harm after being removed from the zone. Aaron Gilbreath, Longreads, "As Innocuous as Plant No. 1," 10 Apr. 2018

Recent Examples on the Web: Adjective

Actress Sydelle Noel embodies a similar ethos by taking on brawny, brassy, alpha woman roles. Abby Haglage,, "4 Black Girls With Big Dreams & The 4 Women Living Them," 13 July 2018 As the alpha brother, Romeo, wild, fun and charmingly manipulative, Pucci is transformed by a long, blond beard. Katie Walsh,, "Review: Lou Taylor Pucci enlivens wild and wooly 'Poor Boy'," 12 July 2018 To combat those slips, the platform is adding visibility tools through a new feature, still in alpha testing, called Cloud Security Command Center. Lily Hay Newman, WIRED, "Google's Fix For the Gaffe Behind So Many Data Leaks," 21 Mar. 2018 He’s been surrounded all his life by alpha women — his late mother was a screaming, hard-drinking firecracker of a woman. New York Times, "Josh Brolin Fears the Summer of Josh Brolin," 20 June 2018 For state officials, a particular source of concern was alpha contamination, which was also found in some of the dust collected in previous years for Kaltofen’s study. Hal Bernton, The Seattle Times, "Study: Traces of radioactive contamination found in homes of six Hanford workers," 14 June 2018 At a summit where both men sought to play the alpha role, the optics were inherently in Trump’s favor. Laignee Barron, Time, "Body Language Experts Reveal What Trump and Kim's Behavior Says About the Singapore Summit," 12 June 2018 In 2015, Zasloff and his colleagues launched a company, Enterin, that is currently testing a compound that slows alpha-synuclein aggregation in the gut. Diana Kwon, Scientific American, "Does Parkinson’s Begin in the Gut?," 8 May 2018 Both are alpha males highly attuned to their own reputations, and each entered office with grand promises of shattering their country's political status quo. Kevin Liptak And Jeremy Diamond, CNN, "Trump begins state visit with Macron discussing his polls," 24 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'alpha.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of alpha


13th century, in the meaning defined at sense 1


1842, in the meaning defined at sense 1

History and Etymology for alpha


Middle English, from Latin, from Greek, of Semitic origin; akin to Hebrew āleph aleph

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Learn More about alpha

Phrases Related to alpha

alpha male

the alpha and omega

Statistics for alpha

Last Updated

22 Sep 2018

Look-up Popularity

Time Traveler for alpha

The first known use of alpha was in the 13th century

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More Definitions for alpha



Financial Definition of alpha

What It Is

The definition of alpha on InvestingAnswersAlpha, also known as "excess return" or "abnormal rate of return," is one of the most widely used measures of risk-adjusted performance. The number shows how much better or worse a fund performed relative to a benchmark. This difference is then attributed to the decisions made by the fund's management.

How It Works

Let's assume you are a portfolio manager who expects your client's portfolio to return 15% next year. The year goes by and the portfolio actually returns 16%. In its most basic sense, the alpha of the portfolio = 16% - 15% = 1%.

Mathematically speaking, alpha is the rate of return that exceeds what was expected or predicted by models like the capital asset pricing model (CAPM). To understand how it works, consider the CAPM formula:

r   =   Rf  + beta * (Rm - Rf )   +   alpha

r = the security's or portfolio's return
Rf  = the risk-free rate of return
beta = the security's or portfolio's price volatility relative to the overall market
Rm  = the market return

The main part of the CAPM formula (except the excess-return factor) calculates what the rate of return on a certain security or portfolio ought to be under certain market conditions. Note that two similar portfolios might carry the same amount of risk (same beta) but because of different alphas, it's possible for one to generate higher returns than the other. This is a fundamental quandary for investors, who always want the highest return for the least amount of risk.

Why It Matters

The fundamental quandary for investors of how get the highest return possible for the least amount of risk can be measured by alpha. It is a measurable way to determine whether a manager's skill has added value to a fund on a risk-adjusted basis.

The very existence of alpha is controversial, however, because those who believe in the efficient market hypothesis (which says, among other things, that it is impossible to beat the market) attribute alpha to luck instead of skill, and base this belief on the fact that most managers fail to beat the market over the long-term.

Source: Investing Answers



English Language Learners Definition of alpha

 (Entry 1 of 2)

: the first letter of the Greek alphabet

: the first version of a product (such as a computer program) that is being developed and tested



English Language Learners Definition of alpha (Entry 2 of 2)

: having the most power in a group of animals or people


al·pha | \ˈal-fə \

Medical Definition of alpha 

(Entry 1 of 2)

1 : the 1st letter of the Greek alphabet symbol Α or α


variants: or α-

Medical Definition of alpha (Entry 2 of 2)

1 : of or relating to one of two or more closely related chemical substances the alpha chain of hemoglobin α-yohimbine used somewhat arbitrarily to specify ordinal relationship or a particular physical form, especially one that is allotropic, isomeric, stereoisomeric, or sometimes polymeric (as in α-D-glucose)

2 : closest in position in the structure of an organic molecule to a particular group or atom also : occurring at or having a structure characterized by such a position α-substitution

More from Merriam-Webster on alpha

Thesaurus: All synonyms and antonyms for alpha

Britannica English: Translation of alpha for Arabic Speakers

Comments on alpha

What made you want to look up alpha? Please tell us where you read or heard it (including the quote, if possible).


lying above or upon

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