ˈgrȯt]ˌhu̇s]ˈdrāpə(r)-, ˈgrät], ]ˌhüs]\ noun
Usage: usually capitalized G&D
Etymology: after Theodor von Grotthuss died 1822 German physicist and John W. Draper died 1882 American chemist
: a statement in physical chemistry: radiation produces photochemical action only through absorption of its energy by the substance affected