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

This was the grandfather of qubits. —Ethan Siegel, Big Think, 8 Oct. 2025

Martinis, in particular, is known for work with a team at Google using such qubits to make record-breaking quantum computers. —Dan Garisto, Scientific American, 7 Oct. 2025

Built for integration Optical spectroscopy and microwave tests showed the molecular qubits align with frequencies already used in silicon photonics. —Aamir Khollam, Interesting Engineering, 2 Oct. 2025

Coherence of qubits is essential for quantum computing, so being able to verify it by detecting anomalous heat exchange could be helpful. —Quanta Magazine, 1 Oct. 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