Heads up display (HUD)
From The Glossary of Digital Photography
A display of information projected onto a transparent screen, such as a window or goggles, through which the viewer is looking. Without looking away, for example, an automobile driver using a HUD can look through the windshield at the road but still see the instruments, such as the speedometer, projected on the clear glass. A term used by Apple's Aperture software to describe its floating panels, such as the Adjustments heads up display (Adjustments HUD).
