Audiovisual captions are natural language descriptions that simultaneously convey both the visual components and auditory events occurring within a video or multimedia recording. Unlike purely visual descriptions that detail visible objects and motions or audio descriptions that capture sound effects and speech in isolation, audiovisual captions integrate information across both sensory modalities into a unified, coherent narrative. In multimodal machine learning and artificial intelligence, these comprehensive descriptions are used to train and evaluate models on tasks such as cross-modal retrieval, automated video captioning, and multimedia question answering, allowing systems to align and interpret concurrent visual scenes and acoustic signals.