Ionic is a front-end framework for developing native-feeling hybrid mobile apps with HTML and Sass. Traditionally, it runs on top of Cordova and Angular, but since Ionic 4 it supports Angular, React, Vue.js and Web Components running on top of Cordova or Capacitor.
Presentation
Ionic Framework is an open-source html5 hybrid mobile application development framework that helps in building cross-platform mobile applications with standard web technologies like html, css, typecript and web-component's.
Ionic Framework is focused on giving a native-like UI experience, built on top of web technologies.
Traditionally, it has used Apache cordova and 
angular. Since January 2019, Ionic 4 allows developers to choose multiple frameworks including angular, react, vue.js, and web components.
Ionic also has a rich Command Line Interface which enables the developers to create, build, test and deploy applications.
Ionic 4 supports multiple frameworks by building its components using stenciljs, a compiler that creates Web Components.
The Ionic Team are also developing an alternative to Cordova, called Capacitor. capacitor is a cross-platform app runtime that allows developers to build web apps that run natively on iOS, Android, Electron and the web.
Official Links:
Website: https://ionicframework.com
Documentation: https://ionicframework.com/docs/
Getting Started: https://ionicframework.com/getting-started
Ionic Showcase: https://showcase.ionicframework.com
