Ruby on Rails is a server-side web application framework written in Ruby that follows the Model-View-Controller (MVC) architectural pattern. MVC separates the application into three interconnected components:

• Model: Manages data and business logic, interacts with the database
• View: Handles presentation layer and user interface
• Controller: Processes requests, coordinates between Model and View

Rails emphasizes convention over configuration and DRY (Don't Repeat Yourself) principles, making development faster and more maintainable.