AVFoundation refers to a framework provided by Apple, which uses Objective-C and Swift for working with audiovisual media on iOS and macOS. AVFoundation enables the handling of various tasks such as recording, editing, playing, and exporting audio and video content. It provides APIs for creating time-based audiovisual compositions, managing tracks, and applying various effects and filters. The framework supports real-time processing and playback of media, facilitating the development of advanced multimedia applications.