Also called dalton. a unit of mass, equal to 1/12 (0.0833) the mass of the carbon-12 atom and used to express the mass of atomic and subatomic particles.

(formerly) a unit of mass, equal to 1/16 (0.0625) the mass of an oxygen atom having atomic mass 16. Abbreviation: amu, AMU

British Dictionary definitions for atomic mass unit

atomic mass unit

noun

a unit of mass used to express atomic and molecular weights that is equal to one twelfth of the mass of an atom of carbon-12. It is equivalent to 1.66 × 10 –27 kgAbbreviation: amu Also called: unified atomic mass unit, dalton

A unit of mass equal to 112 the mass of an atom of the most common isotope of carbon (carbon 12), which is assigned a mass of 12 and has a value of 1.660 X 10-24 grams. A hydrogen atom has a mass of 1 atomic mass unit since its mass is 112 the mass of carbon 12. Also called dalton