be·ta (bātə, bē-)
1. The second letter of the Greek alphabet. See Table at alphabet.
2. The second item in a series or system of classification.
3. A mathematical measure of the sensitivity of rates of return on a portfolio or a given stock compared with rates of return on the market as a whole. A beta of 1.0 indicates that an asset closely follows the market; a beta greater than 1.0 indicates greater volatility than the market.
4. Astronomy The second brightest star in a constellation.
5. Computers The version of a software or hardware product used in a beta test.
1. Being the second-ranked individual of one's sex. Used of social animals: the beta male of the chimpanzee colony.
a. Being in the second position relative to a designated carbon atom in an organic molecule at which an atom or a group may be substituted.
b. Referring to the second of a group of isomers, or molecules of similar origin or properties, determined arbitrarily by those who discover or classify them. Used in combination: beta-estradiol
3. Computers Of or relating to a beta test or the software or hardware involved in a beta test.
[Greek bēta, of Phoenician origin; see byt in the Appendix of Semitic roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.