LWC framework is the Salesforce implementation of a new breed of lightweight frameworks built on web standards, which leverages custom elements, modules, shadow DOM, decorators, templates, and other new language constructs available in ECMAScript 7 and beyond.
Salesforce Lightning Web Components (LWC) is a framework for building user interfaces for Salesforce applications. It is a custom HTML5 and JavaScript-based component library that provides a foundation for building dynamic, responsive user interfaces. LWC is designed to be used with the Salesforce Lightning Component Library, which is a set of pre-built, reusable components that can be used in your Lightning applications.