Orchestrator, as the name suggests, is the central place where you manage the UiPath bots. 

You can deploy and keep track of all your bots from this interface:

The Orchestrator is conveniently accessible through your browser and also through mobile apps. At the time of writing this book, UiPath has apps for iOS (Apple App Store) and Android (Google Play Store). 

The Orchestrator allows multi-tenancy, allowing you to scale easily and enable discrete departmental RPA initiatives. The bottom line is that you can build your first bot and scale up to thousands of bots with this architecture.