1. The first letter of the Greek alphabet. See Table at alphabet.

2. The first one; the beginning.

3. Chemistry The first position from a designated carbon atom in an organic molecule at which an atom or radical may be substituted.

4. Astronomy The brightest or main star in a constellation.

5. 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.

1. Being the highest ranked or most dominant individual of ones sex. Used of social animals: the alpha female of the wolf pack.

2. Chemistry Closest to the functional group of atoms in an organic molecule.

3. Alphabetical.