a unit of mass, exactly one twelfth the mass of a neutral atom of the most abundant isotope of carbon, C: one atomic mass unit equals 1.6605 x 10 gram and is equivalent to 931.48 MeV in energy: symbol amu or u
See atomic mass unit in American Heritage Dictionary 4
noun Abbr. amu
A unit of mass equal to 1/12 the mass of the most abundant isotope of carbon, carbon 12, which is assigned a mass of 12. Also called dalton.