Even though Latin is considered a dead language (no country officially speaks it), its influence upon other languages makes it still important. Latin words and expressions are present in virtually all the languages around the world, as well as on different scientific and academic fields.
Below you will find a list with the most used and important Latin words and expressions, enjoy!
Common Latin Words
Latin/Greek Numeral Prefixes
duo, bi: two
tri, tris: three
quadri, tetra: four
Other Latin/Greek Prefixes
extra: in addition to
General Latin Expressions
a priori: from the former. If you think something a priori, you are conceiving it before seeing the facts. Presupposing.
ad hoc: to this. Ad hoc refers to something that was creating for a specific purpose or situation. An ad hoc political committee, for instance, is formed for one specific case.
ad infinitum: to infinity. Something that goes ad infinitum keeps going forever. You could say that your wife hassles you ad infinitum, for example.
ad valorem: to the value. This expressed is used when something is related to the value of an object or transaction, like an ad valorem tax which is proportional to the value of the product.
ceteris paribus: other things being equal. This expressions if often used in economics where, in order to impact of something on the economy (e.g., inflation or unemployment), you need to hold other variables fixed.
de facto: common in practice, but not established by law. For example, English is the de facto official language of the United States.
honoris causa: for the sake of the honour: This is an honorary degree where an academic institution grants a doctorate to someone without the formal requirements (exams and the like). Usually the person receiving the degree has connections with the University or has made important achievements in a certain field.
in toto: entirely.
mutatis mutandis: with necessary changes. This expression is used to express agreement to something that, however, still need to be changed or amended.
per se: by itself. If something exists per se, for instance, it exists by itself, regardless of external factors.
sic: thus. Sic is usually used in newspapers or other publications (placed within square brackets [sic]) to indicate that the spelling error or unusual phrase on a quotation was reproduced as it was in the source, and therefore it is not an editorial error.
vice versa: the other way around. If you write “John loves Mary, and vice versa,” it means that Mary also loves John.
Q.E.D. (Quod erat demonstrandum): which was to be demonstrated. This Latin abbreviation is often used at the end of mathematical theorems in order to demonstrate that proof is complete.
Legal Latin Expressions
bona fide: good faith. In contract law, for instance, parties must always act in good faith if they are to respect the obligations.
de jure: by law. Some states are currently working on legislation that would make English the de jure official language of the United States.
dictum (plural dicta): a statement that forms part of the judgment of a court.
obiter dicta: a judge’s opinion offered in the course of a judgment but having no legal force.
ex parte: from, by, or for one party in a dispute. An ex parte decision is one decided by a judge without requiring all of the parties to the controversy to be present.
habeas corpus: (we command that) you bring forth the body. In this case, the “body” (corpus) refers to a living person who is being held in prison. The phrase has nothing to do with producing the corpse of an allegedly-murdered person.
ipso facto: by the fact itself. Parents who have deliberately mistreated their child are ipso facto unfit custodians.
mens rea: guilty mind. The U.S. legal system requires that when a crime is committed, the perpetrator must have the intention to commit the crime. For example, a driver who strikes and kills a pedestrian because of faulty brakes is guilty of manslaughter, but not of murder. There was no intent to kill so the mind was not guilty. On the other hand, the wife who repeatedly runs over her husband with her SUV is guilty of murder because of her mens rea.
pro bono: (the original phrase is pro bono publico) for the public good. Sometimes high-priced lawyers come forward to defend suspects who would otherwise have to take their chances with someone from the Public Defender’s office. They work on the case pro bono, i.e., they don’t charge a fee.
prima facie: by first instance – this refers cases with sufficient evidence to warrant going forward with an arraignment.
quid pro quo: something for something. For example, the ADAs (assistant district attorneys) make deals with criminals, giving them shorter sentences in exchange for information that will enable them to convict other criminals. Another example of quid pro quo might occur between two lawyers, each of whom gives up some advantage to gain another.
Famous Latin Phrases
divide et impera: Divide and reign. It was a theory proposed by Niccolò Machiavelli and used previously by the Roman Senate to dominate the Mediterranean.
alea jacta est: the die is cast: This famous phrase was said by Julius Caesar upon crossing the Rubicon. Caesar was violating a law of the Roman Empire, hence why he was playing with luck.
veni vidi vici: I came, I saw, I conquered. Another phrase said by Julius Caesar, this time upon the victory over Pharnaces, king of Pontus.
cogito ergo sum: I think, therefore I am. This phrase was originally said in French by René Descartes, and it represents a corner-stone of the Western philosophy. The Latin translation is more widely used, though.
carpe diem: seize the day. This phrase comes from a poem by Horace. The phrase was made famous when it was used on the movie Dead Poets Society.
deus ex machina: God out of a machine. In ancient Greece when a plot was complicated or tangled, the play writers would just insert a God in the final act in order to solve all the problems. Usually a crane machine was used to drop the actor on stage, hence the name.
homo homini lupus: man is a wolf to men. This phrase was originally said by Plauto, but other philosophers also used it, including Bacon and Hobbes. The meaning is quite straight forward.
This article was written collaboratively by Daniel and Maeve. If you think there is Latin word or expression missing just let us know and we will update it.