Definition
A transparent dome mounted in the upper fuselage of an aircraft, used by the navigator to take celestial sightings of the sun, moon, and stars for position fixing during long-range flight before modern electronic navigation.
Plain English
A clear bubble on top of the aircraft that the navigator looked through to spot stars and use them to figure out where the plane was.
Context Anchor
Seen in older long-range aircraft, military aircraft, and discussions of celestial navigation equipment.
Derivation
From Greek astron meaning star, plus dome from Latin domus meaning house or roof. Literally a 'star dome' — a roof you look through to see the stars.
Why Pilots Care
Largely a historical term now, but it appears in older aircraft documentation and aviation history. Knowing it prevents confusion when reading about long-range flight before GPS and inertial navigation.
Intuition Check
An astrodome is not a planetarium or a display of stars inside the aircraft. It is a real clear window or bubble that lets the crew look outside at the sky.
Example Sentence 1
The navigator climbed up to the astrodome to take a star sighting and confirm the aircraft's position over the Atlantic.
Example Sentence 2
Older long-range aircraft often included an astrodome so the crew could maintain position without ground references.