PhoneGap is an open-source mobile development framework that allows developers to create applications for various platforms using web technologies like HTML, CSS, and JavaScript. It simplifies the process of building cross-platform apps by enabling a single codebase to run on multiple operating systems, such as iOS and Android. Originally developed by Nitobi, PhoneGap was later acquired by Adobe. It provides access to native device features, such as the camera and GPS, through a set of JavaScript APIs, making it easier for web developers to create mobile applications without needing extensive knowledge of native programming languages.