α | alpha

The Greek letter α (alpha) was derived from the ancient Phoenician letter 𐤀 (ʾālep) which, in turn, was derived from 𓃾, the Egyptian hieroglyph of an ox’s head.

The lower-case letter α has found many uses in maths and sciences:

• in astronomy: the brightest star in a constellation. For instance, Betelgeuse is designated as α Orionis
• in biochemistry: α-helix, a type of protein secondary structure
• in inorganic chemistry: a symbol for certain (usually the most common) allotropes, for example α-iron, α-phosphorus, and α-sulphur
• in natural product chemistry: a stereodescriptor used in a number of different ways
• in navigation: a symbol for azimuth
• in neurophysiology: α-waves, a type of brain waves detected by electroencephalography
• in nuclear physics: alpha particle, α or α²⁺, a historical name of doubly ionised helium nuclei (He²⁺) ; α-decay is a radioactive process in which an atomic nucleus emits an α-particle
• in organic chemistry: the α-carbon is the first carbon atom attached to a functional group; α-amino acids are amino acids with an amino group bound directly to the α-carbon
• in pharmacology: α₁ and α₂, subtypes of adrenergic receptors
• in physics: a symbol for angular acceleration
• in physics: the fine-structure constant
• in zoology: α-males and α-females, the highest ranking individuals in a community of social animals

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