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

a

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

b

slang, disparaging : a timid, weak, or submissive person

… [he] is still such a beta he doesn't do solo press conferences.

—Dieter Kurtenbach

compare alpha entry 1 sense 6, sigma

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.

compare alpha entry 1 sense 5

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

beta

2 of 2

adjective

1

: second in position in the structure of an organic molecule from a particular group or atom

beta substitution

—often used in combination

—symbol β

2

slang, disparaging : socially submissive or subordinate : having the character, qualities, or status of a beta

a beta male

Examples of beta in a Sentence

Noun

a program that is currently in beta

Recent Examples on the Web

Noun

The selloff in Bitcoin has mirrored the fall in high-beta stocks, strengthening the case that crypto is now moving in lockstep with broader risk assets. —Denitsa Tsekova, Fortune, 23 Nov. 2025

Hidden in the latest public beta of the Phone by Google app, as spotted by Android Authority, the brand appears to be working on new notification tech which appears on a recipient’s phone telling them your call is urgent. —PC Magazine, 21 Nov. 2025

Adjective

Spirulina is a blue-green algae that contains nutrients, including fat-soluble vitamins, beta carotene, and minerals. —Jennifer Lefton, Verywell Health, 24 Nov. 2025

The beta launch of music videos was far from Spotify’s first foray into the video market. —Steven J. Horowitz, Variety, 12 Nov. 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 at sense 1

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