Elon Musk’s Twitter is X. Its original name is from the dictionary.

The early reaction has been mixed. “Sesame Street” got in on the fun, tweeting an image of a googly-eyed X character: “The letter X will be holding a press conference later today.”

The World Wildlife Federation took a more serious turn, tweeting: “Twitter’s iconic bird isn’t the only one disappearing. Today, one in eight bird species are at risk of extinction.”

How hard is it to rebrand? Maybe ask a few Facebook and Instagram users whether they’re throwing around “Meta Platforms” in conversation, nearly two years after the parent company’s name change.

Companies spend great amounts of money to change their signage, code and advertisements after a name change. They do it because they want to ensure the viability of the business. Musk hasn’t explained why he has set the bird free.

Twitter begins rebrand to ‘X,’ removing bird from company logo

This message was still on the Twitter website Monday morning: “Our logo is our most recognizable asset. That’s why we’re so protective of it.” The webpage was emblazoned with the bird icon that has been central to the creation and name of the business.

Dorsey said the early working name for what became Twitter was “Status,” or “Stat.us.” But he and the other founders decided they wanted to convey the feeling of someone causing their friend’s phone to buzz in their pocket, he told the Los Angeles Times in 2009.

After some brainstorming, they landed on “Twitch.” But that name didn’t bring up the right imagery. (Later someone else would snatch up the word to create another internet giant.)

One of Dorsey’s co-founders, Noah Glass, was looking up other words that started with “tw” in the Oxford English Dictionary when he came across “twitter,” Dorsey told WNYC in 2011.

“And ‘twitter’ means a short inconsequential burst of information, chirps from birds,” he said. “And we were like, that describes exactly what we’re doing here. So it was an easy choice, and we got [the domain name] twitter.com for some very low price, and we named the company Twitter.”

(Glass was later ousted from Twitter, as detailed in Nick Bilton’s book “Hatching Twitter.” After an explosive 2011 Insider article detailed the drama, the platform’s third co-founder, Evan Williams, tweeted an acknowledgment that Glass hadn’t gotten his due: “It’s true that @Noah never got enough credit for his early role at Twitter. Also, he came up with the name, which was brilliant.”)

At first, Dorsey said, they were going to name the company “twttr.” To understand why, travel back to the magical time of 2006, when it was still the Staples Center and not Crypto.com Arena, Prince had reverted back to his non-symbol name and that big building in Chicago was still called the Sears Tower, not the Willis Tower.

In this land of boot-cut jeans, people still used SMS, and that was the basis of what we now (used to?) know as Twitter. You would text the company, and they would post your text online for you.

As Dorsey explained to the L.A. Times, the company needed to have a short code for people to send their tweets. He said they tried to use the name “twttr” because they could just take out the vowels — a very trendy branding choice at the time — and use the five-digit code of letters associated with numbers on the phone keypad.

“But unfortunately Teen People had that code — it was ‘txttp’ [text TP],” Dorsey said. “So we just decided to get an easy-to-remember short code [40404] and put the vowels back in.”

A “twttr” artifact can be seen in the very first tweet.

Dorsey on March 21, 2006, posted: “just setting up my twttr”

“So Twitter was it, and it’s been a big part of our success,” Dorsey told the Times. “Naming something and getting the branding right is really important.”

It isn’t clear why Musk would change the social media company’s “most important asset” and a “brilliant” name. But it is clear that Musk likes the letter X.

The name of his son with singer Grimes is X Æ A-12. Nearly 25 years ago, Musk founded the online bank X.com, which eventually became PayPal. In 2002, Musk introduced his spacecraft manufacturing company, SpaceX. And in 2015, the Tesla founder and CEO released the Model X crossover vehicle.

As of Monday, x.com redirects to the social media website where you can tweet.

Esther Crawford, Twitter’s former head of product, called the rebrand “corporate seppuku,” or ritualistic suicide practiced by samurai. And she chose to communicate that destruction of product on the platform formerly known as Twitter.

“The result is a massive loss of shareholder value,” she wrote.