beta
noun
the second letter of the Greek alphabet (β, B).
beta
American
[bey-tuh, bee-]
/ ˈbeɪ tə, ˈbi- /
noun
betas
plural
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the second letter of the Greek alphabet (β, B).
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the consonant sound represented by the second letter of the Greek alphabet.
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Astronomy. Beta, a star that is usually the second brightest of a constellation.
The second brightest star in Taurus is Beta Tauri.
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Chemistry.
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one of the possible positions of an atom or group in a compound.
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one of two or more isomeric compounds.
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the second of any series, as in chemistry or physics.
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Computers. the phase of hardware or software development in which a product is tested in the environment for which it was designed.
Our newest product, currently in beta with new features being added regularly, is perfect for busy professionals who need to organize their calendars.
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Also called beta coefficient. Also called beta line. Stock Exchange. an arbitrary measure of the volatility of a given stock using an index of the volatility of the market as a whole.
A beta of 1.1 indicates a stock that is 10 percent more volatile than the market.
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Trademark. Beta, a brand of tape format for VCR tape, incompatible with other formats.
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Chiefly British. a grade showing that a student is in the middle or second of three scholastic sections in a class.
adjective
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Computers. being, relating to, or undergoing the phase of product development in which a product is tested in the environment for which it was designed.
The beta version of the new game, featuring a four-player mode, will be unveiled next month.
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(of an animal) having the second-highest rank in a dominance hierarchy.
the beta female in a pack of meerkats.
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Slang: Sometimes Disparaging. being or relating to a man who is perceived to be weak, mild-mannered, and unimpressive.
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beta
1
British
/ ˈbiːtə /
noun
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the second letter in the Greek alphabet (Β, β), a consonant, transliterated as b
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the second highest grade or mark, as in an examination
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(modifier)
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involving or relating to electrons
beta emitter
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relating to one of two or more allotropes or crystal structures of a solid
beta iron
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relating to one of two or more isomeric forms of a chemical compound
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Beta
2
British
/ ˈbiːtə /
noun
Other Word Forms
Noun Inflected Forms
Etymology
Origin of beta
First recorded in 1350–1400; from Latin, from Greek bêta, from Phoenician bt “house,” also the name of the second letter of the Phoenician alphabet; cf. beth
Explanation
Beta is the second letter of the Greek alphabet. It also refers to a preliminary model of software or hardware that's being tested but is not quite a finished product. The Greek letter beta, β, is used in several fields, including statistics, physics, finance, and geometry, to represent different things. Because it's the second letter in the Greek alphabet, right after alpha, it's often used to mean "secondary" or "second in order" — as in a "beta particle," the second type of radiation discovered by Ernest Rutherford. In technology, a beta version of software is in the secondary testing phase, when it's a nearly complete prototype. A company may let some people use the beta version to help work out some kinks before releasing the final version.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Fat accumulation in the liver may also have impaired the ability of pancreatic beta cells to release insulin, contributing to higher blood sugar levels in people in cluster 5.
From Science Daily ● Jul. 28, 2026
He also courted strong and straight — and unavailable — alpha men to whom he appeared happy to play the beta role of political ingénue.
From Salon ● Jul. 13, 2026
With a smarter, more personalized Siri AI rolling out in beta to English-language users later this year, it’s natural to assume the revamped assistant will come to revamped speakers.
From The Wall Street Journal ● Jul. 12, 2026
The new Siri is part of the company’s Apple Intelligence family of features and will be available to users in beta form later this year.
From The Wall Street Journal ● Jun. 9, 2026
This is different from beta decay, in which a neutron is transformed into a proton by the emission of an electron.
From "Big Science" by Michael Hiltzik
Beta cells are the insulin-producing cells in the pancreas.
From Science Daily ● Jul. 26, 2026
Computer modeling indicates that the planet probably travels around Beta Pictoris at a distance of about 30 astronomical units.
From Science Daily ● Jul. 23, 2026
Of the three known planets in the system, Beta Pictoris d has the widest orbit, although it still lies inside the inner boundary of the debris disk.
From Science Daily ● Jul. 23, 2026
The nearby young star Beta Pictoris was already known to have two massive planets, Beta Pictoris b and Beta Pictoris c.
From Science Daily ● Jul. 23, 2026
When Daito’s avatar vanished completely, it left behind a small pile of spinning items on the ground—everything he’d been carrying in his inventory, including the Beta Capsule.
From "Ready Player One: A Novel" by Ernest Cline
While most of those chip makers have “betas” greater than 1—meaning their daily moves in the last few years have been larger than the S&P 500’s moves—all of the stocks above have betas below 1.
From Barron's ● Jun. 16, 2026
Consider the performance of a hypothetical portfolio that buys the 10% of stocks with the highest betas and sells short the decile of stocks with the lowest betas.
From MarketWatch ● Oct. 23, 2025
“We’re betas pretending to be alphas,” Denton said.
From New York Times ● Nov. 3, 2022
If you missed out on those betas, you can at least get some idea of what the game will look like by watching some Overwatch League.
From The Verge ● Aug. 16, 2022
Greek letters move across the undersides of his eyelids: isosceles triangles, betas, sine curves.
From "All the Light We Cannot See" by Anthony Doerr
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
