Any authority which has a legal mandate to govern, administrate a part or aspect of public life, such as all branches of the executive power of a state, province, municipality etc.

plural of public authority

The whole of such public authorities, the governmental administration in the widest sense

plural of appeal to authority

A public authority which operates a port or other transportation infrastructure.

plural of port authority

(Christianity) An epithet of God and of Jesus.

That author of a joint paper who is considered by the publisher to have submitted it for publication.

plural of corresponding author

(rhetoric) Deeming an assertion to be true because of the position or the authority of the person asserting it.