The aerodynamic diameter of a particle having a median mass i.e., the masses of particles above and below this value are equal. It is the diameter that divides the graphical representation of the distribution of mass into two equal area segments also called the mass median diameter (MMD).

Any of various analytical methods in which atoms are ionized, dispersed, and collected according to mass. Allows the ratio of uranium isotopes in a sample to be measured so as to assess portions of natural and depleted uranium.

The MPC is the maximum permissible concentration for exposure for 540 hours during a single calendar quarter of 13 weeks.

See conexes.