WHEREBY Meaning of WHEREBY in English /hwair buy", wair-/ , conj., adv.1. by what or by which; under the terms of which. 2. Obs. by what? how? [ 1150-1200; ME wherby. See WHERE, BY 1 ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012