Update README.md

Author: ergenekonyigit

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://travis-ci.org/electron/electron-api-demos.svg?branch=master)](https://travis-ci.org/electron/electron-api-demos)
 [![JavaScript Standard Style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](http://standardjs.com)
 
-This is a desktop app that interactively and with sample code demonstrates core features of the [Electron](http://electron.atom.io) API. It's built with Electron, too, of course. This app works on Windows, OS X and Linux operating systems.
+This is a desktop app that interactively and with sample code demonstrates core features of the [Electron](http://electron.atom.io) API. It's built with Electron, too, of course. This app works on Windows, macOS and Linux operating systems.
 
 Use this app to see what you can do with Electron and use the source code to learn how to create a basic Electron app.