The power to enforce laws, exact obedience, command, determine, or judge. One that is invested with this power, especially a government or body of government officials: land titles issued by the civil authority. Power assigned to another; authorization: Deputies were given authority to make arrests. A public agency or corporation with administrative powers in a specified field: a city transit authority. An accepted source of expert information or advice: a noted authority on birds; a reference book often cited as an authority. A quotation or citation from such a source: biblical authorities for a moral argument. Justification; grounds: On what authority do you make such a claim? A conclusive statement or decision that may be taken as a guide or precedent. Power to influence or persuade resulting from knowledge or experience: political observers who acquire authority with age. Confidence derived from experience or practice; firm self-assurance: played the sonata with authority.