Android app development refers to the process of creating software applications that can run on the Android operating system, which is the most widely used mobile operating system in the world. Android app development involves creating apps that can be used on smartphones, tablets, smartwatches, and other devices that run on the Android platform.

The Android operating system is based on the Java programming language and is open source, which means that developers can access the source code and modify it as needed. Android app development can be done using a variety of programming languages, including Java, Kotlin, and C++. Developers can use Android Studio, which is the official integrated development environment (IDE) for Android app development, to create, test, and deploy apps.

Android app development involves several stages, including planning, design, development, testing, and deployment. During the planning stage, developers identify the purpose of the app, define the target audience, and create a basic concept of the app's features and functionality. During the design stage, developers create the user interface (UI) and user experience (UX) of the app, as well as the overall visual design.

During the development stage, developers write the code for the app, which involves creating the features and functionality of the app. Testing is done to ensure that the app is functioning as intended and is free of bugs or errors. Once the app has been thoroughly tested and is ready for deployment, it can be published to the Google Play Store, which is the primary app store for Android devices.

Android app development can be used for a wide range of applications, from productivity and business apps to entertainment and gaming apps. It can also be used to create apps for wearable devices, such as smartwatches, as well as for Internet of Things (IoT) devices. With the widespread use of Android devices, Android app development has become an important part of the software development industry.