Alpha — Α / α
Alpha (Α α) is the first letter of the Greek alphabet. The alpha symbol is written Α in uppercase (identical to the Latin A) and α in lowercase, and together with beta it gave the word "alphabet" its name. In math α commonly labels an angle, in statistics it is the significance level (often α = 0.05), and in physics it names alpha particles and the fine-structure constant (≈ 1/137). Copy it with the buttons below, or see how to type Greek letters on any keyboard.
Α α
Copy: Α α
Unicode code points: U+0391 (uppercase), U+03B1 (lowercase).
| Uppercase | Α |
|---|---|
| Lowercase | α |
| Transliteration | a |
| Pronunciation | AHL‑fah |
| Numeric value | 1 |
Etymology and Origin
The name "alpha" comes from the Phoenician letter aleph, which meant "ox." The Greeks adapted this letter around 800 BCE, transforming it from a consonant to the first vowel of their alphabet. The word "alphabet" itself derives from the first two Greek letters: alpha and beta.
Pronunciation
- Ancient Greek: [a] as in "father"
- Modern Greek: [a] as in "father" (unchanged)
- English usage: AL-fah [ˈælfə]
Uses of Alpha in Mathematics
In mathematics, α is one of the most commonly used Greek letters:
- Angles: First angle in triangles, often ∠A = α
- Constants: Fine structure constant in physics (α ≈ 1/137)
- Coefficients: First coefficient in polynomial expressions
- Roots: α and β often name the roots of a quadratic
- Statistics: Significance level in hypothesis testing (typically α = 0.05)
Uses in Science and Engineering
- Physics: Angular acceleration (α = dω/dt)
- Chemistry: Alpha particles (helium nuclei), alpha carbon
- Biology: Alpha helix protein structure, alpha waves in brain
- Engineering: Thermal expansion coefficient, angle of attack
- Astronomy: First/brightest star in constellations (e.g., Alpha Centauri)
Cultural and Symbolic Uses
- "Alpha and Omega": Beginning and end (Christian symbolism)
- Alpha male/female: Dominant individual in social hierarchy
- Software development: Alpha version (early testing phase)
- Finance: Alpha represents excess returns on investment
- Military: NATO phonetic alphabet - "Alpha" for letter A
Mathematical Examples with Alpha
Angle notation: sin(α) + cos(α) = ?
Physics equation: α = Δω/Δt (angular acceleration)
Statistics: P-value < α → reject null hypothesis
Related Letters
- Omega (Ω ω) — the last letter of the alphabet, paired with alpha in "alpha and omega" (Revelation 1:8) to mean beginning and end.
- Beta (Β β) — the second letter, alongside alpha, gives us the word "alphabet." In statistics and software, alpha and beta are conventionally paired (α-test then β-test; α-error and β-error in hypothesis testing).
Writing Tips
- Uppercase Α: Identical to English A - two diagonal strokes meeting at top with horizontal crossbar
- Lowercase α: Not like English a - draw a circle with curved tail extending right
- Common mistake: Don't write lowercase α like English 'a' with straight top
Interesting Facts
- Alpha is the ancestor of the Latin letter A
- In ancient Greek numerals, Α΄ = 1
- The star Alpha Centauri is the closest star system to Earth
- "Alpha" brands often imply leadership or premium quality