C20

C20 or C-20 may be:

• C20 (engineering), a mix of concrete that has a compressive strength of 20 newtons per square millimeter
• HMS C20, a 1910 British C class submarine
• Sauber C20, a 2001 racing car
• C-20, a series designation for military aircraft:
  • C-20 would have been the in-service designation of the Fokker F.32
  • C-20A/B/C/D/E, variants of the Gulfstream III
  • C-20F/G/H/J, variants of the Gulfstream IV
• OMX Copenhagen 20, also known as the OMXC20, Denmark's primary stock market index
• Bill C-20, the Canadian Clarity Act
• C20 (Airport), Berrien Springs or Andrews University Airpark
• C₂₀, the smallest possible fullerene
• Malignant neoplasm of rectum ICD-10 code
• a type of rolling stock in the Stockholm Metro
• The Twentieth Century Society, a British charity which campaigns for the preservation of architectural heritage from 1914 onwards
• Caldwell 20 (The North America Nebula, NGC 7000), an emission nebula in the constellation Cygnus
• C20 Cities now expanded to the C40 Cities or Large Cities Climate Leadership Group
• Shorthand expression of twentieth century