C20

C20 or C-20 may refer to:

==Science and technology== Carbon-20 (C-20 or 20C), an isotope of carbon C20, the smallest possible fullerene (a carbon molecule) C20 (engineering), a mix of concrete that has a compressive strength of 20 newtons per square millimeter Malignant neoplasm of rectum, a type of colorectal cancer (ICD-10 code: C20) Caldwell 20 or North America Nebula, an emission nebula in the constellation Cygnus IEC 60320 C20, a polarised, three pole socket electrical connector C20 (Capacity, 20 hours), C100 (100 hours), battery capacity