ac·u·men (ăkyə-mən, ə-kymən)
Quickness, accuracy, and keenness of judgment or insight: “A brilliant acumen in agricultural matters ... had made the old man a legend in the district” (James Herriot).
[Latin acūmen, from acuere, to sharpen, from acus, needle; see ak- in the Appendix of Indo-European roots.]
Usage Note: The pronunciation (ăkyə-mən), with stress on the first syllable, has long been accepted as a standard pronunciation. It is an Anglicization of an older, traditional pronunciation (ə-kymən) that reflects the word's Latin origin. In our 2016 survey, only 34 percent of the Usage Panel found the older pronunciation acceptable (down from 60 percent in 1997), and only 14 percent preferred it, suggesting that this pronunciation is falling out of use.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.