HD may refer to:
HDMI (High-Definition Multimedia Interface) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device.
HD Radio (HDR) is a trademarked term for the in-band on-channel (IBOC) digital radio technology used by AM and FM radio stations mostly in the United States, Canada and Mexico (with a few implementations outside North America) to transmit audio and data by using a digital signal embedded "on-frequency" immediately above and below a station's standard analog signal, providing the means to listen to the same program in either HD (digital radio with less noise) or as a standard broadcast (analog radio with standard sound quality).
HDFC Bank Ltd. is an Indian banking and financial services company headquartered in Mumbai, Maharashtra.
HD 189733 b is an extrasolar planet approximately 64.5 light-years away from the Solar System in the constellation of Vulpecula.
HDR is an employee-owned engineering firm, specializing in engineering, architecture, environmental and construction services.
HD 209458 b, also given the nickname Osiris, is an exoplanet that orbits the solar analog HD 209458 in the constellation Pegasus, some 159 light-years from the Solar System.
HDBaseT, promoted and advanced by the HDBaseT Alliance, is a consumer electronic (CE) and commercial connectivity standard for transmission of uncompressed high-definition video (HD), audio, power, home networking, Ethernet, USB, and some control signals, over a common category cable (Cat5e or above) using the same 8P8C modular connectors used by Ethernet.