What is Auctoritas?

Legal Definition
Auctoritas is a Latin word and is the origin of English "authority". While historically its use in English was restricted to discussions of the political history of Rome, the beginning of phenomenological philosophy in the 20th century expanded the use of the word.

In ancient Rome, Auctoritas referred to the general level of prestige a person had in Roman society, and, as a consequence, his clout, influence, and ability to rally support around his will. Auctoritas was not merely political, however; it had a numinous content and symbolized the mysterious "power of command" of heroic Roman figures.

Noble women could also achieve a degree of Auctoritas. For example, the wives, sisters, and mothers of the Julio-Claudians had immense influence on society, the masses, and the political apparatus. Their Auctoritas was exercised less overtly than their male counterparts due to Roman societal norms, but they were powerful nonetheless.
-- Wikipedia
Legal Definition
In the civil law. Authority. In old European law. A diploma, or royal charter. A word frequently used by Gregory of Tours and later writers. Spelman.
-- Black's Law Dictionary
Legal Definition
Authority.
-- Ballentine's Law Dictionary