Beta

The second Greek letter, used for beta particles, coefficients and angles.

Also known as: Greek letter beta, Beta symbol, β

ScientificMathematicalEngineering & technicalStandard profile

Meanings

Beta is the second Greek letter and follows alpha through most naming conventions: where alpha took the first quantity, beta takes the second. Its most consequential uses are the beta particle in physics and the beta coefficient in statistics and finance.

Common modern usageVerified fact
Is a letter of the Greek alphabet before it is a symbol: what it denotes is fixed by the field it appears in, not by the character itself. The uses below are the documented conventions, not competing definitions.
Contexts: Mathematics
Common modern usageVerified fact
In physics, denotes a beta particle — an electron or positron emitted in radioactive decay.
Contexts: Mathematics
Common modern usageVerified fact
In statistics, denotes a regression coefficient, or the probability of a type II error.
Contexts: Mathematics
Common modern usageVerified fact
In finance, denotes an asset's volatility relative to the market as a whole.
Contexts: Mathematics
Common modern usageVerified fact
In geometry and trigonometry, denotes an angle, usually the second one labelled.
Contexts: Mathematics
Common modern usageVerified fact
In software, denotes a release made available for testing before general availability.
Contexts: Mathematics
Common modern usageVerified fact
Resembles the Latin letter B closely enough to be misread as one, and the German ß, which is a different character with a different history.
Contexts: Mathematics

Visual description

A tall vertical stroke descending below the writing line, with two rounded bowls stacked against its right side.

Symmetry: none
Orientation: upright

Part of the same system as: Alpha
Alpha and beta are used together as the first and second of a numbered series, in radioactive decay and in labelling generally.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is defined by a current official standard, but multiple independent sources agree.

Sources

Unicode Code Chart: Greek and Coptic (U+0370–U+03FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
Greek alphabet
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for the widely-agreed uses of the letter across fields and for its history. Not used to assert that any one use is the letter's definitive meaning — no body defines that, and the record says so.
Greek letters used in mathematics, science, and engineering
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for the widely-agreed uses of the letter across fields and for its history. Not used to assert that any one use is the letter's definitive meaning — no body defines that, and the record says so.
Beta
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for the widely-agreed uses of the letter across fields and for its history. Not used to assert that any one use is the letter's definitive meaning — no body defines that, and the record says so.

Last reviewed 2026-07-31