Halogen: Any of the four non-metallic elements fluorine, chlorine, bromine and iodine. Related info: Types of lighting
Head (1): The component which records an electrical signal onto magnetic tape, or reads a signal from tape into an electrical signal. Related info: Cleaning video heads
Head (2): The part which the camera is mounted on, atop a tripod, pedestal or other mounting. Allows the camera to pan and tilt. More info: Camera tripods
Headroom: The amount of space between the top of the subject's head and the top of the picture frame. More info: Camera framing
HDBaseT: A digital connection used in home entertainment systems, designed to carry video, audio, ethernet, power and control data over a standard Cat5e/6 cable. More info: HDBaseT
HD DVD: A high-definition DVD format supported by a group of manufacturers led by Toshiba. More info: The HD DVD Format, HD-DVD vs Blu-ray
HDCP: High-bandwidth Digital Content Protection (AKA High-Definition Copyright Protection). A method of copy protection that prevents audio and video signals being copied across digital connections.
HDMI: High-Definition Multimedia Interface. A digital connection used in home entertainment systems. More info: HDMI connectors, HDMI cables
HDTV: High-Definition Television. More info: HDTV formats
Hi8: An analog video format introduced by Sony in 1989. More info: Hi8
HMI: Hydrargyrum Medium-Arc Iodide, a type of light which uses an arc lamp instead of an incandescent bulb to produce light. More info: HMI Lights
Hot (1): An image or part of an image which is excessively bright, i.e. overexposed. More info: Iris & Exposure
Hot (2): The wire in a cable, and the connecting pins, which carry the signal. Related info: Audio cables and connectors
Hyperfocal distance: In cinematography, the distance from the camera beyond which all objects can be brought into acceptable focus. Related info: Focus
Hz: Hertz. Cycles per second.