A mobile application, or "app," is a software program that is designed to run on a mobile device, such as a smartphone or tablet. Mobile apps are typically available for download through app stores such as the Apple App Store or Google Play Store, and they can be used to perform a wide range of tasks, from playing games and listening to music to tracking fitness and managing finances. Mobile apps are developed using programming languages and frameworks specific to the platform they are being built for, such as Swift and Objective-C for iOS, and Java and Kotlin for Android. The process of developing a mobile app involves several stages, including design, development, testing, and deployment.