qu·​bit | \ ˈkyü-bət How to pronounce qubit (audio) \
plural qubits

Definition of qubit

: 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

First Known Use of qubit

1994, in the meaning defined above

History and Etymology for qubit

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."

Keep scrolling for more

Learn More about qubit

Time Traveler for qubit

Time Traveler

The first known use of qubit was in 1994

See more words from the same year

Statistics for qubit

Cite this Entry

“Qubit.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/qubit. Accessed 8 Aug. 2020.

Comments on qubit

What made you want to look up qubit? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Original Meanings Quiz

  • rembrandt painting a young scholar and his tutor
  • Which of the following is the earliest known sense of the word awe?
Spell It

Can you spell these 10 commonly misspelled words?

Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!