ES6, also known as ECMAScript 2015, is the sixth major release of the ECMAScript language specification. It is a scripting language specification standardized by Ecma International, which defines the syntax and semantics of JavaScript. ES6 introduced several new features and improvements to JavaScript, including arrow functions, template literals, destructuring assignments, classes, modules, and more. These features make JavaScript more expressive, concise, and easier to work with. ES6 has significantly influenced the way modern JavaScript applications are developed.