June 1997 First edition

https://en.m.wikipedia.org/wiki/ECMAScript

ECMAScript (or ES)[1] is a trademarked[2] scripting-language specification standardized by Ecma International in ECMA-262 and ISO/IEC 16262. It was created to standardize JavaScript, so as to foster multiple independent implementations. JavaScript has remained the best-known implementation of ECMAScript since the standard was first published, with other well-known implementations including JScript and ActionScript.

https://en.m.wikipedia.org/wiki/Ecma_International

Ecma is a standards organization for information and communication systems.[1] It acquired its current name in 1994, when the European Computer Manufacturers Association (ECMA) changed its name to reflect the organization's global reach and activities. As a consequence, the name is no longer considered an acronym and no longer uses full capitalization.