acme (n.)

"highest point," 1560s, from Greek akme "(highest) point, edge; peak of anything," hence "prime (of life, etc.), the best time" (from PIE *ak-ma-, suffixed form of root *ak- "be sharp, rise (out) to a point, pierce"). In English it was written in Greek letters until c. 1620. The U.S. grocery store chain was founded 1891 in Philadelphia, Pennsylvania.