unit of magnetic moment (the product of a magnet's pole strength and the distance between its poles) used in the study of subatomic particles. The Bohr magneton, named for the 20th-century Danish physicist Niels Bohr, is equal to about 9.273 × 10^-21 erg per gauss per particle. The nuclear magneton, calculated using the mass of the proton (rather than that of the electron, used to calculate the Bohr magneton) equals 1/1,836 Bohr magneton. See magnetic dipole.