Word.ws English Dictionary

known unknown

known unknown noun: an uncertainty of known magnitude, consequence, structure, and probability characteristics; something that we know that we don't know.

Noun

known unknown (plural known unknowns)

  1. An uncertainty of known magnitude, consequence, structure, and probability characteristics; something that we know that we don't know.

Forms of known unknown

pluralknown unknowns

Origin of known unknown

Popularized by Donald Rumsfeld in 2002, though used much earlier.

Questions about known unknown

What does known unknown mean?
Known unknown means an uncertainty of known magnitude, consequence, structure, and probability characteristics; something that we know that we don't know.
What part of speech is known unknown?
Known unknown is a noun.
What is the plural of known unknown?
The plural of known unknown is known unknowns.

Words near known unknown in the dictionary

  1. known the drill
  2. known the score
  3. known the shit
  4. known universe
  5. known universes
  6. known unknown
  7. known unknowns
  8. known what o'clock it was
  9. known what side of one's bread is buttered
  10. known what side of one's bread was buttered
  11. known what side of the bread is buttered

Source and license

Adapted from Wiktionary: known unknown (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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