Coined by Austro-Hungarian-American artist Jack Binder in his 1938 picture feature "If Science Reached the Earth's Core", printed in the October 1938 issue of the science-fiction pulp-magazine Thrilling Wonder Stories as part of a series of similar "If—" articles.
- The state of apparent weightlessness which occurs in a very low gravity field, or in free fall.
1938 October, Jack Binder, “If Science Reached the Earth's Core”, Thrilling Wonder Stories, volume 12, number 2, page 99:
- Starting at the zero-gravity of earth's core, accumulative acceleration is easily built up in a four-thousand-mile tube.
- Brave New Words: The Oxford Dictionary of Science Fiction, Oxford University Press, 2007
- zero-gravity n. at the OED Science Fiction Citations Project