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The Many Meanings and Uses of X [Updated]

The Many Meanings and Uses of X [Updated]

X is one of the most powerful letters in the alphabet. From math to maps, and from voting to kissing, no other letter can be used in so many different ways and mean so many different things.

This article will explore its main uses and also cover the different ways X can be read or pronounced depending on where you find it. Let's begin!

X can equal...

A place on a map

An old-fashioned treasure map lit with a candle

In many adventure stories, the main characters are searching for a treasure that has been hidden for years. Often, there will be a special map that leads the hero to a mysterious place where they can discover the riches no one else could find.

On maps like these, the spot where the treasure is waiting is usually marked with a big X. It's similar to the red marker on a Google map pointing to your destination. Because of this popular usage, the phrase “X marks the spot” has become a common English expression.

A mysterious or unknown person

X is often used when someone’s identity is unknown or is being kept secret. In this case, its usage is similar to a question mark.

No one knows his real identity, so we just call him Mr. X.
There will be a special appearance by "Artist X" at the show. You'll have to come to find out who it is!

In some situations, having an X for a name represents danger or power. That’s why there are many films, books, comics and video games in which either the hero or the villain is named “Mr. X” or something similar.

A film rating

Do you like movies? The movie rating system in the US uses letters and letter-number combinations to indicate the kind of content a film contains. You may know G, PG, PG-13 and R, which are the most common ratings.

However, there was originally another rating above R: X! X-rated films often featured scenes of extreme violence or sexual content. Some movie studios even promoted their films as double- or triple-X to get audiences' attention.

Learn more about movie ratings in our article all about them: 'What Do Movie Ratings Mean? (G, PG, R, etc.)'

An error

A very common usage of X is to indicate errors, and this usage can appear in many different places. For example, a teacher grading student assignments may write an X (often in red ink) next to an incorrect answer. You may see an X on road signs to indicate that a street is closed or to signal to drivers that they are going in the wrong direction. 

Similarly, even if there is no error, X is often used in many types of software to go backward or to close a menu.

A kiss

Two colorful birds kissing each other

A common way to end a letter or text message to someone you have a close relationship with is with an X, which represents a kiss. This is because the shape of the letter is a little like lips pressed together in a kissing position!

Though it can be used alone, it is often used together with O, which represents a hug. So if you say "XOXO" out loud, you would say "hugs and kisses" even though the order of the letters is reversed.

By the way, this X kiss can be either friendly or romantic depending on the relationship of the people in the conversation.

And more!

The multiplication symbol

In mathematics, an "x" represents multiplication. When used this way, we say the word "times." For example, the equation 4 x 2 = 8 would be read as "four times two equals eight."


When measuring the different sides of an object, we use x to separate the different values. This usage is pronounced "by."

An A4 piece of paper is about 8" x 11." ("eight by eleven inches")

An unknown amount

In more advanced mathematics and even in daily conversation, x represents an unknown number or amount. 

2x - 5 = 17
We can only stay for x days before we run out of money.

“Sign here”

A person signing their name by the "X" on official documents

On contracts and other important documents, an X will often indicate the area where you should sign your name. It is usually found at the bottom of the page.


X is the Roman numeral for the number 10. This is commonly used even in the modern day. The operating system for Apple computers after OS 9 was Mac OS X, and the tenth film in the Fast & Furious series of action movies is called Fast X.

A vote

When there is an election and you need to choose between different people or plans of action, it's common to write either a check mark or an X next to your selection. 


In comics and other drawings, Xs over the eyes of a character often means that character is dead.


Several railroad crossing signs in a rural setting filled with trees

At railroad crossings, signs often shorten "crossing" to simply an X. Some signs say "R X R" or "Xing" along with an image of a train to indicate a crossing.

The horizontal axis

On graphs, the x-axis is the horizontal line on the bottom, while the y-axis is the vertical line on the left side.


X is used as a verb meaning to write over something with one or more Xs as a way to cancel or remove it. It's often used together with "out," as in "X out."

We X'd out all of the incorrect information on the document.

X in popular culture

In 2023, the popular social media service Twitter was renamed to X. It is owned by the X Corp., founded by Elon Musk, also in 2023.

Additionally, The X Factor is the name of a well-known singing competition show that originally began in the UK. This title is actually a common idiom which describes a mysterious quality that makes someone or something special or unique. 

This town is not especially beautiful or convenient, but it has an X factor that makes me love it.

Differences in pronunciation

Don't forget that X is pronounced differently depending on its position in a word. Normally, it sounds like ks, like in "fox," "complex" or "experience."

However, there are some words that begin with X, and in these cases it's pronounced like a Z. Most of these words are very scientific and are not useful in daily conversation, but some common examples are "xylophone," a kind of musical instrument, and "xenophobia," which is a fear or hatred of people from other countries or cultures.


X is quite a letter! Depending on the situation, it can mean many different things and can even be read in a variety of ways.

The meanings we've covered in this article are all common in the US and other English-speaking countries, but that doesn't mean it is the same everywhere. Does X have different or additional meanings in your country?