Plain English Meaning
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.
Full 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.
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.