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

By 2019, the estimate was lowered to 20 million physical qubits. — Dan Goodin, ArsTechnica, 23 June 2026

Moments later, dae instructor Kay Detome stood in front of the room, explaining introductory quantum concepts like qubits and entanglement as students followed along on laptops. — P.r. Lockhart, Hartford Courant, 22 June 2026

Quantum computing uses quantum bits or qubits which can be zero, one or something in between. — Arjun Kharpal, CNBC, 17 June 2026

The new 20-qubit IQM Radiance system will operate alongside the lab’s high-performance computing infrastructure. — Georgina Jedikovska, Interesting Engineering, 17 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