Plain English Meaning

A see-through cockpit display that uses a special coated glass to show flight information floating in front of the pilot's eyes, while still letting them see clearly through the windshield.

Full Definition

A type of head-up display that uses a holographic optical element embedded in the combiner glass to project flight symbology into the pilot's forward field of view. The holographic film selectively reflects the specific wavelength of light produced by the HUD projector while allowing nearly all other light to pass through, so the symbology appears bright and sharp without significantly dimming the view of the outside world.

Context Anchor

Seen in HUD discussions, especially where the explains how flight guidance can be shown in the pilot’s forward view.