Attributive and in the genitive. Designating, relating to, or in accordance with an empirical rule governing addition by an ionic mechanism to carbon–carbon multiple bonds, according to which the more negatively charged group of an asymmetrical addendum becomes attached to the carbon atom bonded to the smaller number of hydrogen atoms (because of the relative stability of the intermediate carbenium ion). Chiefly in "Markovnikov('s) rule".
1920s. From the name of Vladimir Vasil′evič Markovnikov, Russian chemist, who proposed the rule in 1870.