unknown

From un- +‎ known, past participle of know. Compare Old English ungecnawen.

• (UK) IPA^(key): /ʌnˈnəʊn/
• (US) enPR: ŭn-nōnʹ, IPA^(key): /ʌnˈnoʊn/

• Audio (US)

  (file)

• Rhymes: -əʊn

unknown (comparative more unknown, superlative most unknown)

1. (sometimes postpositive) Not known; unidentified; not well known.
   • 1897 December (indicated as 1898), Winston Churchill, chapter IV, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., OCLC 222716698, page 58:

     The Celebrity, by arts unknown, induced Mrs. Judge Short and two other ladies to call at Mohair on a certain afternoon when Mr. Cooke was trying a trotter on the track. The three returned wondering and charmed with Mrs. Cooke; they were sure she had had no hand in the furnishing of that atrocious house.

   • 2022 January 12, Chris Hegg, “The secret railway in the woods”, in RAIL, number 948, page 34:

     I suspect that this large and complex military railway system, shrouded in official secrecy for most of its operational life, remains unknown to many people.

   Synonyms: anonymous, unfamiliar, uncharted, undiscovered, unexplored, unidentified, unnamed, unrecognized, unrevealed, unascertained, obscure, unsung

   Antonyms: well-known, famous, known

• unknownly
• unknown quantity

unknown (plural unknowns)

1. (algebra) A variable (usually x, y or z) whose value is to be found.
2. Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.
   • 1957, Ethel Erford Hewitt, Into the Unknown: An Historical Novel, page 351:

     Had God walked close beside her into the unknown?

   • 2003 [2002], Donald Rumsfeld, Hart Seely, editor, Pieces of Intelligence: The Existential Poetry of Donald H. Rumsfeld:

     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.

   • 2020 April 9, Ian Boyd, “We practised for a pandemic, but didn’t brace”, in Nature, volume 580, number 7802, page 9:

     The other priority is getting people to respond well to interventions, especially changes to routine. This is one of the biggest unknowns in these scenarios, and yet compliance can be the most crucial factor in determining whether an intervention works.

3. A person of no identity; a nonentity
   • 1965, Bob Dylan, "Like a Rolling Stone"

     How does it feel

     To be on your own

     With no direction home

     Like a complete unknown

     Like a rolling stone?

unknown

1. past participle of unknow