Lumos – Meaning, Origin and Usage

Any Harry Potter fan will tell you without hesitation the term “lumos” means light.

They may also quote a classic scene from the book in which Ron forgets that he is a wizard until Hermione makes a snide comment to him so Ron quickly realizes he can say “lumos” which emits a light straight out of his wand.

This post unpacks the meaning and origin of this expression.


These Harry Potter nerds described above are exactly correct- lumos does indeed mean light. The term “lumos” comes from the Latin word “lumin” which means simply “light.” Adding an “os” to the end of any Latin word adds the meaning “to have” thus, lumos means literally “to have light.”

The success of the spell used in Harry Potter to light up a wizard or witches wand has translated lately into the digital world. For example, recently Apple has added a feature on their iPhones which enables you to turn on the flashlight simply by saying “Hey Siri, lumos.”

You can also conversely say the phrase “Hey Siri, Nox” to turn off your flashlight, which, coincidentally is another spell in Harry Potter that has Latin roots. We can all feel like characters in Harry Potter with these fun new features! More information can be found in the video (here).

Example Usage

“It’s so dark in here. Lumos!”

“We need lumos.”

“Hey Siri, lumos.”


“ A little bit of lumos will banish the terrors of the night”.


Lumos, as described above, gets its roots from the Latin word “lumin” and the suffix “os,” meaning to have. Latin is an important language for all Romance languages and has strong ties to Catholicism; in fact, in the 4th century, Latin became the proper language of the Catholic church and continued to be its official language up until the 1960’s. It’s no coincidence then, that movies such as “The Exorcist” use Latin phrases while doing magical things like expelling demons out of children, and this culture of intertwining Latin phrases with magic and demons is one we see in our culture throughout much of our history.

Harry Potter has not historically been the only one to use Latin in wizarding spells, Latin and magical spells such as Lumos have gone hand in hand since before the Middle Ages. Due to Latin being known as a dead language, its mysterious nature lends itself well to the mystifying wizarding world. Further, our history of using Latin in religious ceremonies and due to the fact that Latin is at the root of all romance languages, our history of using Latin phrases will continue to be intertwined until time immemorial. The fact that JK Rowling used Lumos and other Latin phrases in the spells used at Hogwarts is no surprise, nor is it unique!

Phrases Similar to Lumos

  • Let there be light!
  • Brighten

Phrases opposite to Lumos

  • Nox- a spell in Harry Potter that turns off the light from the wand.
  • Turn the lights off I’m trying to sleep!
  • To have no light.
  • There is no light in this dungeon, I wish I were a wizard!

What is The Correct Saying?

  • Lumos- to have light.

Ways People May Incorrectly Say Lumos

Lumos is generally pretty easy to understand, but it is always possible for a person to misconstrue a phrase and use it incorrectly- especially if you are a new wizard and are still trying to learn the lingo! It’s important to remember the suffix “os” means to have, thus it could be easy to accidently say “to have” twice, as you can see in the second example below.

  • Lumos the lights off, it’s bed time.
  • We need to have lumos!

Acceptable Ways to Phrase Lumos

  • Lumos!
  • We need lumos, I can’t see anything!
  • Where is my flashlight, I need lumos!
  • Lumos maxima! – This is a spell in Harry Potter that emitted a blinding light as opposed to the flashlight like light the spell Lumos emitted.

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