Definition
A transparent display mounted in the pilot's forward field of view that projects flight information — such as airspeed, altitude, attitude, heading, and flight path guidance — onto a glass combiner so the pilot can read it while looking outside the aircraft.
Plain English
A see-through screen in front of the pilot that shows key flight information in their line of sight, so they don't have to look down at the instrument panel.
Context Anchor
Seen in cockpit equipment descriptions, instrument flying discussions, and lists of installed or inoperative aircraft components.
Derivation
The name describes how it is used: the pilot keeps their head up, looking forward out the windshield, while the display puts the information right there in their line of sight. This contrasts with a head-down display, where the pilot must look down at the panel.
Why Pilots Care
It reduces eyes-down time and helps maintain situational awareness during instrument approaches and low-visibility operations.
Analogy
It is like a car windshield that can show your speed without making you look down at the dashboard.
Intuition Check
A HUD is not an autopilot and it does not fly the aircraft for you. It only displays information where the pilot can see it while looking forward.
Example Sentence 1
On the approach, the captain used the HUD to track the flight path symbol all the way to touchdown without looking back inside.
Example Sentence 2
When the HUD became inoperative the pilot reverted to scanning the conventional instrument panel.