spectrometry , 895 mean activity of an electrolyte in solution, 896 mean (average), , 896 mean catalytic activity rate, , 896 mean current density, 896 mean exchange current density, 897 mean free path, , 897 mean interstitial velocity of the carrier gas in chromatography , 897 mean life, , 898 mean linear range in nuclear chemistry , 898 mean mass range in nuclear chemistry , 898 mean mass rate, , 898 mean residence time of adsorbed molecules , 898 mean substance rate, , 899 mean volume rate, , 899 measurable quantity, 899 measurand, 899 measured excitation spectrum, 899 measured spectrum, 900 measured value in analysis , 900 measurement, 900 measurement resolution in atmospheric trace component analysis , 900 measurement result, 900 measurement solution in analysis , 901 measurement threshold of an analyser , 901 mechanical entrapment, 901 mechanical hygrometer, 902 mechanism of a reaction , 902 mechanism-based inhibition, 902 mechanization in analysis , 903