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

Quantum computers use qubits that leverage superposition and entanglement to process information in ways classical bits cannot, enabling solutions to problems previously insurmountable for even the most advanced supercomputer. —Chuck Brooks, Forbes.com, 13 June 2026

The company said the technology supports its roadmap toward quantum systems capable of operating with hundreds of high-precision logical qubits. —Neetika Walter, Interesting Engineering, 10 June 2026

When that quantum task involved entangling qubits, quantum computers had an advantage over classical computers, as the classical program took ages to run. —Quanta Magazine, 3 June 2026

This sort of stability was always the promise of topological qubits, and why Microsoft originally committed to the system. —ArsTechnica, 3 June 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