carbon 12
noun
the isotopic carbon atom that comprises 99 percent of naturally occurring carbon, and that since 1961 has been used as the standard for atomic weight by representing a unit of 12.00000.
Also
car·bon-12
[kahr-buh n-twelv] /ˈkɑr bənˈtwɛlv/.
Origin of carbon 12
First recorded in 1940–45
Words nearby carbon 12
carbolic acid,
carbolize,
carboloy,
carboluria,
carbon,
carbon 12,
carbon 13,
carbon 14,
carbon 14 dating,
carbon arc,
carbon bisulphide
Scientific definitions for carbon 12
carbon 12
A stable isotope of carbon, having six protons and six neutrons in the nucleus. Carbon 12 makes up most naturally occurring carbon.