beta

1 of 2

noun

be·​ta ˈbā-tə 

chiefly British

ˈbē- 

plural betas

1

: the 2nd letter of the Greek alphabet see Alphabet Table

2

: something or someone designated with the name beta or the Greek letter β especially denoting the second in position, order, or class

3

: 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

The app is still in beta.

4

: beta particle

beta emissions

5

: 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

Beta measures a stock's price volatility—or risk—compared with the market in general …

—Marlys J. Harris

6

: beta wave

The findings could also help scientists better understand other beta-associated disorders, such as Parkinson's disease or obsessive compulsive disorder …

—Brown University News Release (Providence, Rhode Island)

beta

2 of 2

adjective

: 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

Recall's long road to release involved a rushed initial almost-launch, harsh criticism of its (then mostly nonexistent) security protections, multiple delays, a major under-the-hood overhaul, and five months of testing in Microsoft's Windows Insider beta program. —ArsTechnica, 25 Apr. 2025

The carrier made a splash during the Super Bowl with a commercial that teased the launch of a cellular Starlink beta service for all US users, regardless of carrier. —Michael Kan, PC Magazine, 24 Apr. 2025

Adjective

Duolingo launched a beta version of a chess course on Tuesday, April 22. —Greta Cross, USA Today, 23 Apr. 2025

Where possible, introduce a beta environment for early testing with a select group of users before a full rollout. —Pooja Jain, Forbes.com, 9 Apr. 2025

Word History

Etymology

Noun

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

First Known Use

Noun

14th century, in the meaning defined at sense 1

Adjective

1862, in the meaning defined above

Phrases Containing beta

• A-beta
• amyloid beta
• amyloid beta peptide
• amyloid beta protein
• beta-adrenergic
• beta-amyloid
• beta-amyloid peptide
• beta-amyloid protein
• beta-blocker
• beta-carotene
• beta cell
• beta decay
• beta-endorphin
• beta globulin
• beta-glucan
• beta hydroxy acid
• beta interferon
• beta-lactamase
• beta-oxidation
• beta particle
• beta ray
• beta-receptor
• beta test
• beta-thalassemia
• beta wave
• interferon beta

Rhymes for beta

• data
• theta
• zeta
• oligochaeta
• peseta
• punctata
• polychaeta

Kids Definition

beta

noun

be·​ta

ˈbāt-ə

: the 2nd letter of the Greek alphabet

—Β or β

Medical Definition

beta

1 of 2 noun

be·​ta

ˈbāt-ə, chiefly British ˈbē-tə

1

: the second letter of the Greek alphabet

—symbol Β or β

2

: beta particle

3

: beta wave

beta

2 of 2 adjective

variants or β-

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