noun
: the ratio of the illumination from windows at any point indoors to that out in the open, the test surface being horizontal in each case — called also window-efficiency ratio
noun
: the ratio of the illumination from windows at any point indoors to that out in the open, the test surface being horizontal in each case — called also window-efficiency ratio
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012