be·​ta | \ ˈbā-tə How to pronounce beta (audio) , chiefly British ˈbē- \

Definition of beta

 (Entry 1 of 2)

1 : the 2nd letter of the Greek alphabet — see Alphabet Table
3 : a measure of the risk potential of a stock or an investment portfolio expressed as a ratio of the stock's or portfolio's volatility to the volatility of the market as a whole
4 : a nearly complete prototype of a product (such as software) the beta version also : a stage of development in which a product is nearly complete but not yet ready for release released in beta

Definition of beta (Entry 2 of 2)

: second in position in the structure of an organic molecule from a particular group or atom beta substitution often used in combination symbol β

Examples of beta in a Sentence

Noun a program that is currently in beta
Recent Examples on the Web: Noun Zoom said a preliminary beta of its end-to-end encryption feature would begin in July. Lily Hay Newman, Wired, "Zoom Reverses Course and Promises End-to-End Encryption for All Users," 17 June 2020 Right now, only Pixel users back to version 2 can install the beta, but phones from other manufacturers such as OnePlus will be jumping onboard in a few weeks. Popular Science, "The Android 11 Public Beta is out now—here are some of its exciting features," 13 June 2020 Around 100 beta-testers have taken advantage of the protests this week to shovel more food into VizPol’s machine-learning algorithm. The Economist, "Supremacist safari A birdwatchers’ app inspires a field-guide to protesters’ symbols," 13 June 2020 The Android 11 beta includes changes to notifications, such as a new bubble pop up, an easier way to take screen shots, and many other tweaks. Adam Lashinsky, Fortune, "GrubHub sells, but not to Uber," 11 June 2020 After canceling its planned Android 11 Beta Show YouTube livestream for June 3, Google Wednesday dropped the first public Android 11 beta for Pixel 2 phones and later. Michael Simon, PCWorld, "Google quietly releases Android 11 public beta with few notable features," 10 June 2020 Three patients with limb-girdle muscular dystrophy Type 2E who got the high dose of Sarepta’s SRP-9003 produced greater levels of the protein beta-sarcoglycan. Bailey Lipschultz,, "Sarepta gene therapy win helps to validate broader platform," 8 June 2020 Vitamin C-rich fruits (oranges, grapefruit, etc.) are also good, as are beta-carotene–rich carrots. Barbara Brody, Better Homes & Gardens, "Eye Doctors Debunk 5 Common Myths (Plus, 3 Ways to Keep Your Eyes Healthy)," 7 Apr. 2020 Moderate alcohol consumption is associated with reduced levels of beta amyloid, the protein that forms the brain plaques of Alzheimer’s disease, a new study suggests. Nicholas Bakalar, New York Times, "Moderate Drinking Tied to Lower Levels of Alzheimer’s Brain Protein," 5 Mar. 2020 Recent Examples on the Web: Adjective Android 11, released in its beta version this month on new Pixel phones, introduces a new feature, called Controls. TheWeek, "Google wants to declutter your phone screen," 20 June 2020 As always, this is beta software and likely will have a few bugs. Jacob Krol, CNN Underscored, "Android 11 is official. Here's what's new and how to get the beta," 10 June 2020 About a third of the participants also underwent a PET (positron emission tomography) brain scan to measure deposits of tau and beta amyloid, two proteins which cause Alzheimer's disease, the most common type of dementia. Sandee Lamotte, CNN, "Negative thinking linked to dementia in later life, but you can learn to be more positive," 7 June 2020 Several executives, including Janice Min, left Quibi during its beta phase, and the company parted with another key team member in recent weeks: Megan Imbres, the top marketing executive, who declined to comment. Nicole Sperling, New York Times, "Jeffrey Katzenberg Blames Pandemic for Quibi’s Rough Start," 11 Apr. 2020 WhatsApp Pay began beta testing two years ago but hasn’t been launched yet. Ananya Bhattacharya, Quartz India, "One table that shows how massive the Facebook-Reliance Jio universe can be," 29 Apr. 2020 But what was shown is nearly identical to the beta vehicles Lucid has been showing off—albeit shinier and with a proper interior. Roberto Baldwin, Car and Driver, "Lucid Shows 400-Mile-Range Air Electric Sedan to Future Owners," 14 Feb. 2020 Because beta blockers cause a direct decrease in heart rate, this patient population may have a slower heart rate than would be typical for an untreated patient group, resulting in an underestimation of true AFib heart rates for a larger population. John Nosta, Fortune, "Should consumers be wary of Apple’s heartbeat monitoring app?," 26 Feb. 2020 But how beta-amyloid leads to the devastation of tau has never been precisely clear. Karen Weintraub, Scientific American, "Possible Missing Link in Alzheimer’s Pathology Identified," 16 Jan. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'beta.' 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 beta


14th century, in the meaning defined at sense 1


1862, in the meaning defined above

History and Etymology for beta


Middle English betha, from Latin beta, from Greek bēta, of Semitic origin; akin to Hebrew bēth beth

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Time Traveler for beta

Time Traveler

The first known use of beta was in the 14th century

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Statistics for beta

Last Updated

24 Jun 2020

Cite this Entry

“Beta.” Dictionary, Merriam-Webster, Accessed 4 Jul. 2020.

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More Definitions for beta



Financial Definition of beta

What It Is

Beta is a measure of a stock's volatility relative to the overall market. It is most often calculated using a stock's movements relative to the S&P 500 Index over the trailing 12-month period.

How It Works

A stock's beta is determined by analyzing how much its return fluctuates in relation to the overall market return. A stock with a beta of 1.0 will tend to move higher and lower in lockstep with the overall market. Stocks with a beta greater than 1.0 tend to be more volatile than the market, and those with betas below 1.0 tend to be less volatile than the underlying index. Stocks with betas of zero generally move independently of the broader market. And finally, stocks with negative betas tend to move in the opposite direction relative to the broader market. When the S&P tumbles, stocks with negative betas will move higher, and vice versa.

For example, a stock with a beta of 2.0 is usually twice as volatile as the broader market. If the S&P 500 were to fall by -10% next year, then the stock would be expected to fall about -20% (assuming that the stock behaves similar to how it has in the past). The stock would also be expected to gain more in an up market.

Beta is a measure of systematic risk.

Why It Matters

The definition of beta on InvestingAnswersBeta can help investors choose investments that match their specific risk preferences. A risk-averse investor, for example, may want to avoid overweighting their portfolio with high-beta stocks to avoid excessive volatility.

Individual stock betas are extremely important when putting together a portfolio of assets. A diversified portfolio consisting of assets with different betas lowers the overall risk of the portfolio.

Investors should note that beta is calculated using past price fluctuations and does not ensure that a security will behave the same going forward. Beta is used (most frequently in the Capital Asset Pricing Model, or CAPM) to forecast expected return of a stock or portfolio, not the actual return.

Source: Investing Answers


How to pronounce beta (audio)

English Language Learners Definition of beta

: the second letter of the Greek alphabet
: a version of a product (such as a computer program) that is almost finished and that is used for testing


be·​ta | \ ˈbāt-ə, chiefly British ˈbē-tə \

Medical Definition of beta

 (Entry 1 of 2)

1 : the second letter of the Greek alphabet symbol Β or β
variants: or β-

Medical Definition of beta (Entry 2 of 2)

1 : of or relating to one of two or more closely related chemical substances the beta chain of hemoglobin β-yohimbine used somewhat arbitrarily to specify ordinal relationship or a particular physical form and especially one that is allotropic, isomeric, stereoisomeric, or sometimes polymeric (as in β-D-glucose)
2 : second in position in the structure of an organic molecule from a particular group or atom also : occurring at or having a structure characterized by such a position beta substitution
3 : producing a zone of decolorization when grown on blood media used of some hemolytic streptococci or of the hemolysis they cause

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More from Merriam-Webster on beta

Rhyming Dictionary: Words that rhyme with beta

Spanish Central: Translation of beta

Nglish: Translation of beta for Spanish Speakers

Britannica English: Translation of beta for Arabic Speakers Encyclopedia article about beta

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