al·​pha | \ ˈal-fə How to pronounce alpha (audio) \

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

Keep scrolling for more

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 latter helps regular blood sugar and insulin levels.. Brussels sprouts also contain an antioxidant called alpha-lipoic acid that’s been studied for its potential ability to help improve insulin function. Cynthia Sass, Mph,, "7 Health Benefits of Brussels Sprouts," 9 July 2019 Five alphas in such a short time frame would test the ER’s limits, Anderson thought. Washington Post, "Doctor says Virginia Beach shooting tested emergency room," 6 July 2019 With Simmons as the lead ballhandler and Embiid as their alpha dog, Harris’ ability to succeed in a complementary role is key to Philadelphia’s offensive balance. Ben Golliver, The Denver Post, "76ers emerge from inventive free agency as true contenders," 3 July 2019 Everything is a tough sell for the Ravens, who haven’t been this devoid of marquee names since the great alpha-male purge after their championship season in 2012. Mike Preston,, "Preston: Ravens enter new era lacking star power, seeking new faces of the franchise," 21 June 2019 The feature is currently in the alpha testing phase and is made available through Google's interactive entertainment company FameBit, which offers in-house branded content. Dalvin Brown, USA TODAY, "Google announced new AR YouTube filters that let users virtually try on makeup," 19 June 2019 There are three types of omega-3s: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). Jaclyn London, Ms, Rd, Cdn, Good Housekeeping, "The One Nutrient You Probably Aren't Getting Enough Of, According to a Nutritionist," 15 Apr. 2019 The deaths of a pack’s more experienced alphas can fragment its social structure enough to disrupt hunting, breeding, rearing, and territory defense. Josh Adler, National Geographic, "Making peace in the Golan Heights—between humans and wolves," 11 Apr. 2019 Lawrence craved the American’s freedom without surrendering his own alpha-male prerogative, recoiling from a charity of spirit that was a common sense of citizenship to Whitman. Peter Schjeldahl, The New Yorker, "How to Celebrate Walt Whitman’s Two-Hundredth Birthday," 17 June 2019

Recent Examples on the Web: Adjective

In a brief chat with Ars, Soulstorm Executive Producer Bennie Terry III revealed that the game (and its explosions and alpha effects) has been scaled with current-gen console performance in mind. Sam Machkovech, Ars Technica, "Oddworld: Soulstorm gameplay: Abe’s old-school return is a beautiful thing," 6 June 2019 More young talent is needed, but so is a nasty, alpha-type player who can set the tone up front and ease the burden on the secondary and linebackers. 2. Terez A. Paylor, kansascity, "Here are the Chiefs’ five biggest needs heading into next season | The Kansas City Star," 9 Mar. 2018 The enormous clouds emit large amounts of ultraviolet light with a spectral line produced by hydrogen ions, known as a Lyman-alpha line. Jay Bennett, Popular Mechanics, "Giant Glowing Space Blob's Power Source Discovered," 21 Sep. 2016 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

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.

See More

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

Keep scrolling for more

Learn More about alpha

Statistics for alpha

Last Updated

14 Jul 2019

Look-up Popularity

Time Traveler for alpha

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

See more words from the same century

Keep scrolling for more

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 How to pronounce alpha (audio) \

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).


having no luck

Get Word of the Day daily email!

Test Your Vocabulary

What's that Smell?! Quiz

  • wide eyed dog smelling rose
  • Someone who is hircine smells like a:
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!