legal theory

a priori

A priori signals an assertion that is based on prior knowledge or intuition. In Latin, the term literally means ‘from [the] former’. An a priori determination is formed prior to investigation.

For example:


a priori assumption

An a priori assumption is an assumption that is presumed to be true without any assessment of the facts or without further proof. A priori is a Latin term that refers to a theoretical deduction made on a subject without a precise and detailed...

ab initio

Ab initio is a Latin term that means "from the beginning” or “from inception.” Ab initio is used to indicate that some fact existed from the start of a relevant time period. It is often used as part of the phrase “void ab initio,” meaning...

abandoned property

Abandoned property is defined as personal property left by an owner who intentionally relinquishes all rights to its control. Real property may not be abandoned; see adverse possession.


At common law, a person...

advocacy of illegal action

The advocacy of illegal action is a category of speech not protected by the First Amendment. It is also sometimes referred to as the advocacy of illegal conduct.

First addressed in Whitney v. California (1927), the Supreme...


In negotiations, “anchoring” refers to the common tendency of giving undue weight to the first value or number put forth, and to then inadequately adjust from or counter the first value or number, or the “anchor.”

Thus the...


Arguendo is a Latin term meaning "in arguing" or "for the sake of argument". When one assumes something arguendo, the person is asserting a hypothetical statement to be true for the purpose of argument, regardless of whether that statement...


An argument is both the process of giving reasons for believing something is true as well as the term used to describe the reason(s) given.

An argument is also a disagreement between two or more persons, in which opposing...


Authority is the official permission or right to act, often on behalf of another. Authority may also be a person or institution that has power over another person.

Authority as agency is the power to act on behalf of another...


To authorize means to grant authority; to empower. It may also mean to formally or officially approve.

[Last updated in June of 2021 by the Wex Definitions Team]