Beta

Not to be confused with B, Betta, or Ve (Cyrillic).

For the German eszett, see ß. For the Chinese radical, see 阝. For the Malayalam script, see ദ. For other uses, see Beta (disambiguation).

Beta (UK: /ˈbiːtə/, US: /ˈbeɪtə/; uppercase Β, lowercase β, or cursive ϐ; Ancient Greek: βῆτα, romanized: bē̂ta or Greek: βήτα, romanized: víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Ancient Greek, beta represented the voiced bilabial plosive IPA: [b]. In Modern Greek, it represents the voiced labiodental fricative IPA: [v] while IPA: [b] in borrowed words is instead commonly transcribed as μπ. Letters that arose from beta include the Roman letter ⟨B⟩ and the Cyrillic letters ⟨Б⟩ and ⟨В⟩.

Name

Like the names of most other Greek letters, the name of beta was adopted from the acrophonic name of the corresponding letter in Phoenician, which was the common Semitic word *bait ('house'). In Greek, the name was βῆτα bêta, pronounced [bɛ̂ːta] in Ancient Greek. It is spelled βήτα in modern monotonic orthography and pronounced [ˈvita].

History

See also: Archaic Greek alphabets

The letter beta was derived from the Phoenician letter beth .

The letter Β had the largest number of highly divergent local forms. Besides the standard form (either rounded or pointed, ), there were forms as varied as (Gortyn), and (Thera), (Argos), (Melos), (Corinth), (Megara, Byzantium), and (Cyclades).

Uses

The Greek alphabet on an ancient black figure vessel, with the characteristically angular beta of the time

Algebraic numerals

In the system of Greek numerals, beta has a value of 2. Such use is denoted by a number mark: Β′.

Computing

See also: Software release life cycle § Beta, and Alpha–beta pruning

Finance

Beta is used in finance as a measure of (historical; pseudo-implied) financial asset sensitivity to the relevant benchmark index. Conditional on the benchmark index, the resulting beta value can vary considerably (S&P500 vs NASDAQ vs ETF of a specific industry).

Beta should not be confused with standard deviation (or the semi-variance, which considers only negative returns): the preferred measure of the "riskiness" (historical volatility of returns) of a financial asset or a portfolio in isolation.

Beta can be calculated as the covariance of a financial asset (or portfolio) with its benchmark index, divided by the variance of the benchmark index. Since the industry of finance gravitates towards return generating activities, typically the historical returns (percentage changes) are used in the calculations Beta values (among others). There are numerous other methods a financial analyst can employ to derive Beta values if historical prices are not available. Beta values change over time (company restructuring; industry sentiment; endo/exogenous factors). Beta values also vary, conditional on the time period used in calculating a Beta value. Beta values can be negative, which infers the existence of financial assets which historically, tended to move in opposite directions to one another by some unit value. It would seem these are the optimal "hedges" to offset market-draw-downs, during periods of market-stress and poor liquidity Beta values can vary dramatically, and previously low or even negative correlations converge to "1".

A beta of 1.5 implies that for every 1% change in the value of the benchmark index, the portfolio's value tends to change by 1.5%. The greater the absolute value, the greater the implied move.

International Phonetic Alphabet

In the International Phonetic Alphabet, Greek minuscule beta denotes a voiced bilabial fricative [β].

A superscript version may also indicate a compressed vowel, like [ɯᵝ].

Meteorology

Beta has twice been used to name an Atlantic Basin tropical cyclone:

• Hurricane Beta, in 2005
• Tropical Storm Beta, in 2020

Mathematics and science

Beta is often used to denote a variable in mathematics and physics, where it often has specific meanings for certain applications. In physics a stream of unbound energetic electrons is commonly referred to as beta radiation or beta rays. Decays producing electrons or their antiparticles are called beta decays. In regression analysis, ⟨B⟩ symbolizes nonstandardized partial slope coefficients, whereas ⟨β⟩ represents standardized (standard deviation-score form) coefficients; in both cases, the coefficients reflect the change in the criterion Y per one-unit change in the value of the associated predictor X. β is also used in biology, for instance in β-Carotene, a primary source of provitamin A, or the β cells in pancreatic islets, which produce insulin.

β is sometimes used as a placeholder for an ordinal number if α is already used. For example, the two roots of a quadratic equation are typically labelled α and β.

In spaceflight, beta angle describes the angle between the orbit plane of a spacecraft or other body and the vector from the sun.

β is sometimes used to mean the proton-to-electron mass ratio.

The uppercase letter beta is not generally used as a symbol because it tends to be rendered identically to the uppercase Latin B.

Rock climbing terminology

The term "beta" refers to advice on how to successfully complete a particular climbing route, boulder problem, or crux sequence.

Slang

Main article: Alpha and beta male

Beta male, or simply beta, is a slang term for men derived from the designation for beta animals in ethology, along with its counterpart, alpha male. The term has been used as a pejorative self-identifier among members of manosphere communities, particularly incels, who do not believe they are assertive or traditionally masculine, and feel overlooked by women. It is also used to negatively describe other men who are not assertive, particularly in heterosexual relationships.

Statistics

In statistics, beta may represent type II error, or regression slope.

Typography

In some high-quality typesetting, especially in the French tradition, a typographic variant of the lowercase letter without a descender is used within a word for ancient Greek: βίβλος is printed βίϐλος.

In typesetting technical literature, it is a commonly made mistake to use the German letter ß (a s–z or s–s ligature) as a replacement for β. The two letters resemble each other in some fonts, but they are unrelated.

Videotape formats

"Beta" can be used to refer to several consumer and professional videotape formats developed by Japan's Sony Corporation. Although similarly named, they are very different in function and obsolescence.

• Betamax was the name of a domestic videotape format developed in the 1970s and 1980s. It competed with the Video Home System (VHS) format developed by the Japanese Victor Company, to which it eventually succumbed. The Betamax format was also marketed Betacord by (Sanyo); some cassettes were simply labeled "Beta", and the logo was a lower-case beta. Betamax lost in the market and is an oft-used example of a technically superior solution that failed due to market forces.
• Betacam, including Beta SP and DigiBeta, is a family of professional videotape formats launched in 1982 that was the de facto standard for professional video, advertising, and television production through the 2000s. The formats outlasted analog NTSC television, and their scarcity today is because the industry has moved to HD formats.

Character encodings

• Greek Beta

Character information

Preview	Β		β		ϐ		ᵝ		ᵦ
Unicode name	GREEK CAPITAL LETTER BETA		GREEK SMALL LETTER BETA		GREEK BETA SYMBOL		MODIFIER LETTER SMALL BETA		GREEK SUBSCRIPT SMALL LETTER BETA
Encodings	decimal	hex	dec	hex	dec	hex	dec	hex	dec	hex
Unicode	914	U+0392	946	U+03B2	976	U+03D0	7517	U+1D5D	7526	U+1D66
UTF-8	206 146	CE 92	206 178	CE B2	207 144	CF 90	225 181 157	E1 B5 9D	225 181 166	E1 B5 A6
Numeric character reference	Β	Β	β	β	ϐ	ϐ	ᵝ	ᵝ	ᵦ	ᵦ
Named character reference	Β		β
DOS Greek	129	81	153	99
DOS Greek-2	165	A5	215	D7
Windows 1253	194	C2	226	E2
TeX			\beta

• Coptic Vida

Character information

Preview	Ⲃ		ⲃ
Unicode name	COPTIC CAPITAL LETTER VIDA		COPTIC SMALL LETTER VIDA
Encodings	decimal	hex	dec	hex
Unicode	11394	U+2C82	11395	U+2C83
UTF-8	226 178 130	E2 B2 82	226 178 131	E2 B2 83
Numeric character reference	Ⲃ	Ⲃ	ⲃ	ⲃ

• Latin Beta

Character information

Preview	Ꞵ		ꞵ
Unicode name	LATIN CAPITAL LETTER BETA		LATIN SMALL LETTER BETA
Encodings	decimal	hex	dec	hex
Unicode	42932	U+A7B4	42933	U+A7B5
UTF-8	234 158 180	EA 9E B4	234 158 181	EA 9E B5
Numeric character reference	Ꞵ	Ꞵ	ꞵ	ꞵ

• Mathematical Beta

Character information

Preview	𝚩		𝛃		𝛣		𝛽		𝜝		𝜷
Unicode name	MATHEMATICAL BOLD CAPITAL BETA		MATHEMATICAL BOLD SMALL BETA		MATHEMATICAL ITALIC CAPITAL BETA		MATHEMATICAL ITALIC SMALL BETA		MATHEMATICAL BOLD ITALIC CAPITAL BETA		MATHEMATICAL BOLD ITALIC SMALL BETA
Encodings	decimal	hex	dec	hex	dec	hex	dec	hex	dec	hex	dec	hex
Unicode	120489	U+1D6A9	120515	U+1D6C3	120547	U+1D6E3	120573	U+1D6FD	120605	U+1D71D	120631	U+1D737
UTF-8	240 157 154 169	F0 9D 9A A9	240 157 155 131	F0 9D 9B 83	240 157 155 163	F0 9D 9B A3	240 157 155 189	F0 9D 9B BD	240 157 156 157	F0 9D 9C 9D	240 157 156 183	F0 9D 9C B7
UTF-16	55349 57001	D835 DEA9	55349 57027	D835 DEC3	55349 57059	D835 DEE3	55349 57085	D835 DEFD	55349 57117	D835 DF1D	55349 57143	D835 DF37
Numeric character reference	𝚩	𝚩	𝛃	𝛃	𝛣	𝛣	𝛽	𝛽	𝜝	𝜝	𝜷	𝜷

Character information

Preview	𝝗		𝝱		𝞑		𝞫
Unicode name	MATHEMATICAL SANS-SERIF BOLD CAPITAL BETA		MATHEMATICAL SANS-SERIF BOLD SMALL BETA		MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL BETA		MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL BETA
Encodings	decimal	hex	dec	hex	dec	hex	dec	hex
Unicode	120663	U+1D757	120689	U+1D771	120721	U+1D791	120747	U+1D7AB
UTF-8	240 157 157 151	F0 9D 9D 97	240 157 157 177	F0 9D 9D B1	240 157 158 145	F0 9D 9E 91	240 157 158 171	F0 9D 9E AB
UTF-16	55349 57175	D835 DF57	55349 57201	D835 DF71	55349 57233	D835 DF91	55349 57259	D835 DFAB
Numeric character reference	𝝗	𝝗	𝝱	𝝱	𝞑	𝞑	𝞫	𝞫

These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.