The noun authority has 7 senses (first 6 from tagged texts)
1. (18) authority, authorization, authorisation, potency, dominance, say-so -- (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")
2. (6) authority -- ((usually plural) persons who exercise (administrative) control over others; "the authorities have issued a curfew")
3. (3) authority -- (an expert whose views are taken as definitive; "he is an authority on corporate law")
4. (2) assurance, self-assurance, confidence, self-confidence, authority, sureness -- (freedom from doubt; belief in yourself and your abilities; "his assurance in his superiority did not make him popular"; "after that failure he lost his confidence"; "she spoke with authority")
5. (1) agency, federal agency, government agency, bureau, office, authority -- (an administrative unit of government; "the Central Intelligence Agency"; "the Census Bureau"; "Office of Management and Budget"; "Tennessee Valley Authority")
6. (1) authority, authorization, authorisation, sanction -- (official permission or approval; "authority for the program was renewed several times")
7. authority -- (an authoritative written work; "this book is the final authority on the life of Milton")