<p><strong>Noun</strong></p><ul><li>the first letter of the Greek alphabet (A, α).</li><li>the vowel sound represented by the first letter of the Greek alphabet.</li><li>the first; the beginning.</li><li>Alpha, Astronomy: used to designate the brightest star in a constellation: Alpha Arietis is the brightest star in Aries.</li><li>Chemistry: one of two or more isomeric compounds.</li><li>the first in a series of related items: frequently used in chemistry and physics.</li><li>Computers: an early phase of hardware or software development, in which the product is tested by its developers or manufacturers: alpha test (def). Some modules are complete and ready for consumers while others are still in alpha.</li><li>Chiefly British: a mark or grade corresponding to an A. Compare beta (def 9), gamma (def 9).</li><li>alpha male (def).</li></ul><p><strong>Adjective</strong></p><ul><li>(of an animal) having the highest rank in a dominance hierarchy: the alpha female of an elephant pack.</li><li>being the most dominant, powerful, or assertive person in a particular group.</li><li>Slang: Sometimes Disparaging. being or relating to a man who is perceived to be assertive, successful, and sexually dominant.</li><li>alphabetical: Put the files in alpha order.</li><li>Computers: being, relating to, or undergoing the early phase of product development in which a product is tested by its developers or manufacturers: alpha test (def). The initial release is really an alpha version only available to developers.</li><li>Chemistry: relating to or linked to the carbon atom closest to a particular group in an organic molecule.</li></ul>