An Android Launcher is a customizable interface for Android devices that allows users to change the look and feel of their home screen and app drawer. It provides options to rearrange icons, apply themes, and add widgets, enhancing the user experience and personalization. Launchers can also improve functionality by offering features like gesture controls, app organization, and search capabilities. Popular examples include Nova Launcher, Microsoft Launcher, and Action Launcher, each providing unique features to cater to different user preferences and needs.