imaginary unit


Definition of imaginary unit

: the positive square root of minus 1 denoted by i or + √-1

Examples of imaginary unit in a Sentence

Recent Examples on the Web The introduction of this one new non-real number — i, the imaginary unit — launched an entirely new mathematical world to explore. Quanta Magazine, "The (Imaginary) Numbers at the Edge of Reality," 25 Oct. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'imaginary unit.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of imaginary unit

circa 1911, in the meaning defined above

Keep scrolling for more

Learn More about imaginary unit

Time Traveler for imaginary unit

Time Traveler

The first known use of imaginary unit was circa 1911

See more words from the same year

Statistics for imaginary unit

Cite this Entry

“Imaginary unit.” Dictionary, Merriam-Webster, Accessed 2 Dec. 2020.

Comments on imaginary unit

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


Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
Spell It

Can you spell these 10 commonly misspelled words?

Dictionary Devil

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!