What is Auctor?

Legal Definition
Auctor is Latin for author or originator. The term is used in Scholasticism for a "renowned scholar", and in biological taxonomy for the scientist describing a species or other taxon. The term is widely replaced by author in English-language works.

Auctor also refers to a person who donates the genetic material used to make a clone.

Auctor is the name of a journal for postgraduate students of Classics, published from Royal Holloway (University of London).
-- Wikipedia
Legal Definition
Among the Romans the seller was called auctor; and public, sales were made by fixing a spear in the forum, and a person who acted as crier stood by the spear the catalogue of the goods to be sold was made in tables called auctionariae.
-- Bouviers Law Dictionary
Legal Definition
In the Roman law. An auctioneer. In the civil law. A grantor or vendor of any kind. In old French law. A plaintiff. Kelli am.
-- Black's Law Dictionary
Legal Definition
A plaintiff; a principal; an auctioneer.
-- Ballentine's Law Dictionary