the first letter of the Greek alphabet (A, ?).

the vowel sound represented by this letter.

the first; beginning.

( initial capital letter ) Astronomy . used to designate the brightest star in a constellation.

Chemistry . one of two or more isomeric compounds.

the first in a series of related items

frequently used in chemistry and physics.

Chiefly British . a mark or grade corresponding to an A. Compare beta ( def. 8 ) , gamma ( def. 9 ) .

8.

(esp. of animals) having the highest rank of its sex in a dominance hierarchy

the alpha female.

being the most prominent, talented, or aggressive person in a group

the alpha male of investment bankers.

Chemistry . pertaining or linked to the carbon atom closest to a particular group in an organic molecule.

noun

beginning , first , start