Alpha (Α, α) Definition

Alpha (Α, α) is the first letter of the Greek alphabet. In the system of Greek Numerals, it has a value of 1. It was derived from the Phoenician and Hebrew letter aleph which is an ox or leader. Letters that arose from alpha include the Latin A and the Cyrillic letter А. In English, the noun alpha is used as a synonym for beginning, or first (in a series), reflecting its Greek roots.

Usage in Mathematics & Science

The letter alpha has several different uses such as for the following:

Alpha radiation, angular acceleration, alpha particles, alpha carbon and strength of electromagnetic interaction (as Fine-structure constant).
Alpha also stands for thermal expansion coefficient of a compound in physical chemistry. It is also commonly used in mathematics in algebraic solutions representing quantities such as angles.
In mathematics, the letter alpha is used to denote the area underneath a normal curve in statistics to denote significance level when proving null and alternative hypotheses.
In zoology, it is used to name the dominant individual in a wolf or dog pack.
In aerodynamics, the letter is used as a symbol for the angle of attack of an aircraft and the word alpha is used as a synonym for this property.
The uppercase letter alpha is not generally used as a symbol because it tends to be rendered identically to the uppercase Latin A.
In finance, it is a financial measure denoting the difference between a fund's actual return and its expected return, given its risk level (as measured by beta). In this case a positive alpha indicates that a fund has performed better than expected based on its risk (beta), whereas a negative alpha indicates poorer performance versus what was expected.

Greek Alphabet

The letters of the Ancient Greek Alphabet, which are frequently utilized in math and science:

Greek Alphabet
Symbol		Letter	Symbol		Letter
Uppercase	Lowercase	Letter	Uppercase	Lowercase	Letter
Α	α	Alpha	Ν	ν	Nu
Β	β	Beta	Ξ	ξ	Xi
Γ	γ	Gamma	Ο	ο	Omicron
Δ	δ	Delta	Π	π	Pi
Ε	ε	Epsilon	Ρ	ρ	Rho
Ζ	ζ	Zeta	Σ	σ	Sigma
Η	η	Eta	Τ	τ	Tau
Θ	θ	Theta	Υ	υ	Upsilon
Ι	ι	Iota	Φ	φ	Phi
Κ	κ	Kappa	Χ	χ	Chi
Λ	λ	Lambda	Ψ	ψ	Psi
Μ	μ	Mu	Ω	ω	Omega