Explanation
Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources (e.g. fonts) on a web page to be requested from another domain outside the domain from which the first resource was served. A web page may freely embed cross-origin images, stylesheets, scripts, iframes, and videos.
Note on the History of CORS:
Cross-origin support was originally proposed by Matt Oshry, Brad Porter, and Michael Bodell of Tellme Networks in March 2004 for inclusion in VoiceXML 2.1 to allow safe cross-origin data requests by VoiceXML browsers.
In May 2006 the first W3C Working Draft was submitted. In March 2009 the draft was renamed to
"Cross-Origin Resource Sharing" and in January 2014 it was accepted as a W3C Recommendation.
References: https://en.wikipedia.org/wiki/Cross-origin_resource_sharing