We all know a bit of Latin. Even when you don’t realize it, you’re stumbling upon Latin phrases we still use all the time. You probably already know that Latin was the language of the ancient Romans. However, were you aware that the name of the language can be traced back to present-day Lazio, the region where Rome is located? At the time of the Roman Empire it was called Latium.

Thanks to the unstoppable expansion of the empire, Latin became the official language in large parts of Europe and northern Africa, in addition to Greek, of course. When the Roman Empire fell, its dialects fragmented into the Romance languages that many of us speak and learn today. But Latin itself didn’t completely disappear. It continued to be used in fields such as science, politics and religion, which is why many Latin expressions still exist in the 21st century.

How many of these would you recognize? Here’s a list of 15 of my favorite Latin expressions and their precise origins.

1. Alea iacta est

Literal meaning: “The die is cast.”

Imagine Julius Caesar crossing the river Rubicon. What, you can’t? Well, it was a symbolic act that basically commenced the Second Civil War in the Roman Republic. And there was no way back. This expression means that we have passed the point of no return.

You just handed in your exam? Well, alea iacta est.

2. Alter Ego

Literal meaning: “The other I”

“The other I” — a different person with a completely different personality. The term was coined in the 20th century, when psychologists discovered dissociative identity disorder. A person with an Alter Ego is a person who leads a double life… but it’s no excuse to behave badly and then blame the “other you”!

3. Ante meridiem / Post meridiem 

Literal meaning: “Before midday / after midday”

Even if you haven’t heard these phrases aloud, that doesn’t mean they aren’t Latin phrases we still use. You probably know them by their abbreviations: “a.m.” and “p.m.” I know, this article is going to reveal the meaning of so many acronyms you will feel like you finally understand a bigger part of your own language. In this case, you finally get to understand your alarm clock’s language!

4. Ars longa, vita brevis

Literal meaning: “Art is long, life is short.”

A fancy guy with a fancy name, Hippocrates of Kos, and also a fancy job — he is considered the father of modern medicine — once said this. It indicates the effort and dedication required to make something sublime that will last forever, whereas the life of the human accomplishing the task is brief.

5. Carpe Diem

Literal meaning: “Seize the day”

Horace said this in the First Century BCE, before Drake popularized a different phrase with a similar meaning: YOLO.

6. Cave Canem

Literal meaning: “Beware of the dog”

The “Cave Canem” inscription was first found in Pompeii, the Roman city that was buried in ash after Vesuvius erupted in 79 AD. The “beware of the dog” sign was written at the entrance to one of the houses. We humans haven’t changed that much, have we?

7. Cogito, ergo sum

Literal meaning: “I think, therefore I am.”

This phrase was first uttered by the mathematician, philosopher and scientist René Descartes (1596-1650). This fundamental proposition of Western philosophy has become one of the most famous statements in history.

8. Delirium Tremens

Literal meaning: “Off the furrows” + “Trembling”

Coined in 1813 by British physician Thomas Sutton, Delirium Tremens is the medical term for withdrawal syndrome from alcohol. This is where the phrase “being delirious” comes from.

9. Errare humanum est

Literal meaning: “To err is human.”

This phrase has been repeated over and over since ancient times, since failure is a constant feature throughout history. The author credited with this famous statement is Cicero, a Roman politician and lawyer. The full sentence, “errare humanum est, sed perseverare autem diabolicum” (anyone can err, but only the fool persists in his fault) is basically the “epic fail” of Roman times.

Here’s a theoretical conversation between two ancient Roman friends:

• “Darn! It’s pouring rain and I am wearing my sandals again.”
• “No worries, mate. Errare humanum est.“

10. Exempli gratia

Literal meaning: “For example”

Finally, you have discovered where the shortening “e.g.” come from! Once again, with those abbreviations.

11. Id est

Literal meaning: “It is”

The natural follow-up: If you get “i.e.” confused with “e.g.” maybe knowing the full Latin phrases can help you differentiate.

12. Memento mori

Literal meaning: “Remember that you will die.”

This phrase comes from a rather peculiar custom back in Ancient Rome. When the Emperor was celebrating a victory with a parade, a servant would whisper in his ear memento mori to remind him that he was human, not a God. This servant was probably the first party pooper of all times.

Nowadays, this concept is used in art and literature to represent the fleeting nature of life.

13. Requiescat in pace

Literal meaning: “Rest in Peace”

And you thought “R.I.P.” came from English? Nah, it’s all Latin.

14. Veni, vidi, vici

Literal meaning: “I came, I saw, I conquered.”

Another very famous phrase attributed to Julius Caesar, after he achieved a very quick victory in a short war. Also very eligible to be tattooed, together with Carpe Diem or YOLO.

15. Verba volant, sed scripta manent

Literal meaning: “Spoken words fly away, written words remain.”

This phrase, that actually sounds pretty romantic, was said by Caius Titus to the Roman Senate addressing the problem of oral agreements, because he believed official things had to be written down.

Now that you know where these Latin phrases we use still come from, what are you waiting for? Start a game of trivia and show off some of your newly acquired, meticulous classic knowledge! Roll the dice, alea iacta est!

Illustrations by Marta Duarte Dias.