What is the difference between Apps and Extensions?

An app is very similar to an application which you might install on your desktop or laptop computer. You must open the app in order to use it. An Extension is an "enhancement" to the Chrome web browser and it allows for enhanced capabilities when browsing web pages or using web-based applications. In reality, there isn't much difference between the two and most users will not even know if they are using an app, an extension, or just a traditional web page.