An HDMI (High-Definition Multimedia Interface) cable transmits digital video and audio signals in one cable, connecting a source device like a computer or gaming console to a display like a TV or projector. Different versions of HDMI (e.g., HDMI 1.4, 2.0, 2.1) offer varying bandwidth to support higher resolutions like 4K and 8K, increased refresh rates, and advanced features like HDR (High Dynamic Range) and eARC (Enhanced Audio Return Channel). The cable's quality is important, as a low-grade cable can limit the performance of high-end devices.