The term 'zero-gee' is a modern compound, originating in mid-20th century aerospace and science fiction jargon. It combines 'zero', denoting the complete absence of a quantity, with 'gee', a phonetic respelling of the letter 'G' used as shorthand for the standard force of gravity. Literally, it means "zero gravity," directly describing the physical condition. The logic of the construction is transparent and technical, created to succinctly label the novel experience of weightlessness encountered in spaceflight or free-fall, where the sensation of gravitational pull is absent.

Structure: zero (none) + gee (gravity) zero: From Italian 'zero', ultimately from Arabic 'ṣifr' meaning 'empty, nothing'. In this compound, it functions as a quantifier meaning 'none'. gee: A colloquial abbreviation for 'gravity', specifically the force of Earth's gravity. It originates from the initial 'g' in 'gravity', pronounced as a letter name. It functions as the core noun being modified.