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

From the transistor to tomorrow’s intelligent networks, topological qubits all the way to the first networks on the moon, the story has always been about pushing boundaries. —Cathy Hackl, Forbes.com, 12 June 2025

This provides redundancy against errors in individual physical qubits. —IEEE Spectrum, 10 June 2025

The single qubit in their system reads and organizes information in the oscillators but doesn’t perform the actual computation, as qubits do in other quantum computers. —Stephen Ornes, Quanta Magazine, 9 June 2025

Rather than relying on 1s and 0s that represent data, quantum computers use qubits to solve complicated problems quickly. —Usman Javaid, Forbes.com, 6 June 2025

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 acknowledgements 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