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

The Urgency Of Convergence The quantum threat timeline remains uncertain, but powerful quantum computers, over 10,000 qubits in size, may be capable of breaking existing encryption protocols in coming years. —Antonio Sanchez, Forbes.com, 8 Sep. 2025

For years, Muschik used qubits to simulate quantum electrodynamics, the quantum theory of the electromagnetic field. —Shalma Wegsman, Quanta Magazine, 5 Sep. 2025

In quantum computers, for instance, qubits are fragile and prone to errors. —Rupendra Brahambhatt, Interesting Engineering, 30 Aug. 2025

Building quantum computers requires chips made up of qubits, which are the basic units of quantum information. —Karoline Leonard, Austin American Statesman, 30 July 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