log·a·rithm (lôgə-rĭth′əm, lŏgə-)
The power to which a base, such as 10, must be raised to produce a given number. If nx = a, the logarithm of a, with n as the base, is x; symbolically, logn a = x. For example, 103 = 1,000; therefore, log10 1,000 = 3. The kinds most often used are the common logarithm (base 10), the natural logarithm (base e), and the binary logarithm (base 2).
[New Latin logarithmus : Greek logos, reason, proportion; see leg- in the Appendix of Indo-European roots + Greek arithmos, number; see ar- in the Appendix of Indo-European roots.]
log′a·rithmic (-rĭthmĭk), log′a·rithmi·cal (-mĭ-kəl) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.