marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"
official permission or approval; "authority for the program was renewed several times"
the power or right to give orders or make decisions; "he has the authority to issue warrants"; "deputies are given authorization to make arrests"; "a place of potency in the state"
an authoritative written work; "this book is the final authority on the life of Milton"
an expert whose views are taken as definitive; "he is an authority on corporate law"
(usually plural) persons who exercise (administrative) control over others; "the authorities have issued a curfew"
a device designed to provide additional strength; "the cardboard backing was just a strengthener"; "he used gummed reinforcements to hold the page in his notebook"