qubit

noun

qu·​bit ˈkyü-bət 

plural qubits

: a unit of computing information that is represented by a state of an atom or elementary particle (such as the spin) and can store multiple values at once due to the principles of quantum mechanics

And the most basic truth of quantum mechanics dictates that you cannot measure a qubit without destroying the superposition. The register that said 1 and 0 will randomly collapse into 1 or 0.

—George Johnson

compare bit entry 3 sense 1

Examples of qubit in a Sentence

Recent Examples on the Web

That coming 17-qubit demonstration will be the real scaling test. — John Koetsier, Forbes.com, 7 Aug. 2026

The firm used its Promethium platform alongside IBM’s 156-qubit Heron superconducting quantum processor. — Neetika Walter, Interesting Engineering, 7 Aug. 2026

Crucially, photon loss can be easily detected with the right hardware, without needing additional qubits required to run an error-correction code. — ArsTechnica, 5 Aug. 2026

Word History

Etymology

qu- (in quantum entry 2) + bit entry 4, probably formed with punning allusion to cubit

Note: According to the American physicist Benjamin Schumacher, in the acknowledgments to a paper ("Quantum coding," Physical Review A, vol. 51, issue 4 [April, 1995], p. 2747), "The term 'qubit' was coined in jest during one of the author's many intriguing and valuable conversations with W. K. Wootters, and became the initial impetus for this work."

First Known Use

1994, in the meaning defined above

Rhymes for qubit

• cubit