- (astronomy) A large planet composed mostly of gaseous hydrogen and helium, along with methane and ammonia; possibly with a solid core.
1954, Blish, James, “Solar Plexus”, in Beyond Human Ken, Random House, page 106:
- A quick glance over the boards revealed that there was a magnetic field of some strength near by, one that didn't belong to the invisible gas giant revolving half a million miles away.
large planet of gas
- Brave New Words: The Oxford Dictionary of Science Fiction, Oxford University Press, 2007, pp. 75–76
- gas giant n. at the OED Science Fiction Citations Project