Electron is to dekstop operating systems what Cordova (PhoneGap) is to mobile operating systems.

Electron lets you wrap a web browser inside a desktop app so that you can write code once and deploy it to multiple desktop operating systems.

Electron allows you to use the native menu and notification systems for operating system the app is running on, allowing you apps to feel a bit less like a wrapped web app, and more like a full-fledged desktop application.