From Middle English knowen, from Old English cnāwen.

Morphologically know + -n.

• (RP) IPA: /nəʊn/
• (America) enPR: nōn, IPA: /noʊn/
• (New Zealand) IPA: /ˈnɐʉn/, /ˈnɐʉ.wən/

known (comparative better known, superlative best known)

1. Identified as a specific type; famous, renowned.

   Antonyms: unknown

   He was a known pickpocket.

   • 1664 April 4 (date written; Gregorian calendar), Samuel Pepys, Mynors Bright, transcriber, “March 25th, 1664 (Lady day)”, in Henry B[enjamin] Wheatley, editor, The Diary of Samuel Pepys […], volume IV, London: George Bell & Sons […]; Cambridge: Deighton Bell & Co., published 1894, →OCLC ↗, page 85 ↗:

     Being not knowne, some great persons in the pew I pretended to, and went in, did question my coming in.

2. Accepted, familiar, researched.

   Antonyms: unknown

• French: connu
• German: bekannt
• Italian: conosciuto, noto
• Portuguese: conhecido
• Russian: изве́стный
• Spanish: conocido

known (plural knowns)

1. Any fact or situation which is known or familiar.

   You have to tell the knowns from the unknowns.

   • 2012, Thomas Dougherty, Antibiotic Discovery and Development, volume 1, page 39:

     The biological dereplication tool may identify major knowns in a mixture, but it may miss novel minor components.

2. (algebra) A constant or variable the value of which is already determined.

1. past participle of know