Brocards

A brocard is a legal principle/term, expressed in Latin. 

When I attended law school in England, the Lecturers stressed the importance of using brocards in exams. The reason was that its correct usage illustrated a thorough understanding of the subject matter and therefore resulted in better grades.
Now that I am a Law Lecturer, I want to also ensure that my students are very familiar with the terms, hence this list:


Ab Initio
From the beginning

Inadimplenti non est adimplendum 

"One has no need to respect his obligation if the counter-party has not respected his own." This is used in civil law to briefly indicate a principle (adopted in some systems) referred to as the synallagmatic contract

Dura lex, sed lex 

"The law [is] harsh, but [it is] the law".

Ignorantia legis non excusat 

"Ignorance of the law is no excuse." 

In claris non fit interpretatio 

When a rule is clearly, there is no need to interpret. (i.e., self-explanatory)

Iura novit curia 

The judge knows the law (technically, there is no need to "explain the law" or the legal system to a judge/justice in any given petition).

Nemo dat quod non habet

You cannot give what you do not have. This is a principle widely cited when considering the transfer of property rights, and is most commonly understood as referring to those situations where title to certain property held by the transferee may be void if the transferor never had title to that property in the first place.

Nullum crimen, nulla poena sine praevia lege poenali 

No crime, no punishment without a previous penal law

Pacta sunt servanda

Agreements must be kept

Res inter alios acta vel iudicata, aliis nec nocet nec prodocet 

What has been agreed/decided between people (a specific group) can neither benefit nor harm a third party (meaning: two or more people cannot agree amongst each other to establish an obligation for a third party who was not involved in the negotiation; furthermore, any benefit that may be established will have to be accepted by the third party before it can be implemented). This is called "Privity of Contract" in Contract Law.

Restitutio in integrum - Restoration to original condition. Generally used in the Law of Tort.

Ubi lex voluit, dixit; ubi noluit, tacuit 

When the law wanted to regulate the matter in further detail, it did regulate the matter; when it did not want to regulate the matter in further detail, it remained silent (in the interpretation of a law, an excessively expansive interpretation might perhaps go beyond the intention of the legislator, thus we must adhere to what is in the text of the law and draw no material consequences from the law's silence)

Here is a list of many more brocards!