$\alpha$ — Alpha

Lowercase alpha (α) most often denotes angular acceleration — the rotational counterpart of linear acceleration. In particle physics it is the fine-structure constant, and in thermodynamics the coefficient of thermal expansion.

SI unit: rad/s² (as angular acceleration)

Used in

• Angular acceleration in τ = Iα
• Thermal expansion ΔL = αL₀ΔT
• Fine-structure constant ≈ 1/137