the highest point; summit; peak: The empire was at the acme of its power.
Origin of acme
First recorded in 1610–20, acme is from the Greek word akmḗ point, highest point, extremity
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the culminating point, as of achievement or excellence; summit; peak
Word Origin for acme
C16: from Greek akmē
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
"highest point," 1560s, from Greek akme "(highest) point, edge; peak of anything," from PIE root *ak- "sharp" (see acrid). Written in Greek letters until c.1620. The U.S. grocery store chain was founded 1891 in Philadelphia, Pennsylvania.
Online Etymology Dictionary, © 2010 Douglas Harper