alpha

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The first letter of the Greek alphabet. See Table at alphabet.
2. n. The first one; the beginning.
3. n. Chemistry The first position from a designated carbon atom in an organic molecule at which an atom or radical may be substituted.
4. n. Astronomy The brightest or main star in a constellation.
5. n. The mathematical estimate of the return on a security when the return on the market as a whole is zero. Alpha is derived from a in the formula R_i = a + bR_m, which measures the return on a security (R_i) for a given return on the market (R_m) where b is beta.
6. adj. Being the highest ranked or most dominant individual of one's sex. Used of social animals: the alpha female of the wolf pack.
7. adj. Chemistry Closest to the functional group of atoms in an organic molecule.
8. adj. Alphabetical.

Century Dictionary and Cyclopedia

1. n. The first letter in the Greek alphabet (A, α), answering to A.
2. n. The first; the beginning: as in the phrase “alpha and omega,” the beginning and the end, the first and the last, omega being the last letter of the Greek alphabet.
3. n. As a classifier: In astronomy, the chief star of a constellation. In chem., the first of two or more isomerous modifications of the same organic compound, as alpha-naphthol, in distinction from beta-naphthol.
4. n. In natural history, the first subspecies, etc.
5. n. [capitalized] The name given by Carl Neumann, the mathematical physicist, to a supposed body to which all motion, especially motion of rotation, is relative. It has been said that Newton originated this idea, but that is incorrect. Newton believed that space is a really existing thing, and he suggested that there might possibly be a body which is really in absolute rest relatively to real space. The conception of the body Alpha, which was originated by Neumann, arose, on the contrary, from a difficulty which the theory of Leibnitz (that space is not an existent thing, hut is merely an image embodying certain general laws of the relations between things) meets in the circumstance that, according to the accepted doctrine of Newton's three laws of motion, motion of rotation (as it is ascertained, for example, by Foucault's pendulum experiment) is absolute and not merely relative motion. Neumann, and others who accept Leibnitz's theory of the entire relativity of space, seek to explain rotation by supposing that there is a body Alpha, which is not indeed absolutely at rest, as Newton thought it possible that some body might be (since these persons are of opinion that absolute place and absolute motion are phrases without meaning), hut which is the body to which the motion spoken of in the three laws of motion ought to be understood to be relative. Ernst Mach undertakes to show that this body Alpha is really the universe as a whole, which virtually comes to saying that it is the starry heavens as a whole. The objection to this is that it makes objects the most remote from any given body the principal factors which determine the motions of that body. Now, according to that epistemological psychology which makes space an image embodying the laws of the relations of things, this image must be supposed to be so constituted as to make those things which principally affect one another appear to be near one another. According to Tait, there is no need of any body Alpha, since, so far as rotation and rectilinearity of motion are concerned, we have only to assume, as a definition, that rotation is relative to lines of force fixed within a body having no dynamic effects of rotation.

Wiktionary

1. n. The name of the first letter of the Greek alphabet (Α,  α), followed by beta. In the Latin alphabet it is the predecessor to A.
2. n. Latin alpha
3. n. sciences The name of the symbols Α and α used in science and mathematics, often interchangeable with the symbols when used as a prefix.
4. n. finance The return of a given asset or portfolio adjusted for systematic risk.
5. n. An alpha male.
6. n. informal, abbreviation Alphabet.
7. adj. Designates the first in an order of precedence.
8. adj. associated with the alpha male/female archetype.
9. adj. astronomy Designates the brightest star in a constellation.

GNU Webster's 1913

1. n. The first letter in the Greek alphabet, answering to A, and hence used to denote the beginning.

WordNet 3.0

1. adj. first in order of importance
2. n. the beginning of a series or sequence
3. adj. early testing stage of a software or hardware product
4. n. the 1st letter of the Greek alphabet