An Audio API is a set of programming instructions that allows developers to work with audio data in software applications. It provides tools for playing, recording, and manipulating sound, making it easier to create audio features in games, music apps, and other multimedia projects. These APIs enable interaction with audio hardware and software, allowing for tasks like adjusting volume, applying effects, and streaming audio. Popular examples of Audio APIs include Web Audio API for web applications and OpenAL for game development, which help developers integrate sound seamlessly into their projects.