App bar is a horizontal bar located at the top of an application interface. It serves as the primary navigation header and typically contains elements like the application logo, page title, navigation links, and essential actions. It might also incorporate a search bar or other context-specific actions.

App bar often remains fixed when users scroll, keeping crucial navigation options within easy reach. This component plays a key role in defining the overall user interface architecture, providing consistency across different views, and contributing significantly to user orientation and a smooth, efficient user experience.