unknown unknown

Hello, you have come here looking for the meaning of the word unknown unknown. In DICTIOUS you will not only get to know all the dictionary meanings for the word unknown unknown, but we will also tell you about its etymology, its characteristics and you will know how to say unknown unknown in singular and plural. Everything you need to know about the word unknown unknown you have here. The definition of the word unknown unknown will help you to be more precise and correct when speaking or writing your texts. Knowing the definition ofunknown unknown, as well as those of other words, enriches your vocabulary and provides you with more and better linguistic resources.

English

Etymology

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

Noun

unknown unknown (plural unknown unknowns)

  1. An uncertainty of unknown magnitude, consequence, structure, and probability characteristics, possibly with completely unsuspected existence; something that we don't know that we don't know.
    • 1970, United States Congress. Senate. Committee on the Judiciary. Subcommittee on Antitrust and Monopoly, Competition in Defense Procurement – 1969: Hearing, Ninety-first Congress, page 166:
      This means there are technical unknowns, unknown unknowns, and technical uncertainties in the contract.
    • 2002 February 12, Donald Rumsfeld, “Defense.gov News Transcript: DoD News Briefing – Secretary Rumsfeld and Gen. Myers, United States Department of Defense (defense.gov)”, in Defense.gov Transcript Archive, archived from the original on 2016-08-10:
      Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones.
    • 2014 January 29, Kenneth Chang, “Beings not made for space: After years of missions, health problems of astronauts elude doctors”, in International New York Times, page 7:
      NASA officials often talk about the "unknown unknowns" – the unforeseen problems that catch them by surprise.

Synonyms

Related terms

See also