X is Twitter.

Rules

X is Twitter because Twitter is renamed to X.
Ten or 10 is Twitter because its Roman number is X.
The kanji "十" is Twitter because it means 10.
The addition symbol "+" is Twitter because it looks like "十".
The multiplication symbol "$\times$" is Twitter because it looks like X.
The asterisk mark "*" is Twitter because it is used as multiplication in some programming languages.
In the Twitter context, addition and multiplication are completely the same thing.

(ordered by what I noticed)

X	→	Twitter
ABCDEFGHIJKLMNOPQRSTUVWXYZ	→	ABCDEFGHIJKLMNOPQRSTUVWTwitterYZ
Extension	→	ETwittertension
X-axis	→	Twitter-aTwitteris
y = f(x)	→	y = f(Twitter)
x86	→	Twitter86
X.Org Foundation	→	Twitter.Org Foundation
X Window System	→	Twitter Window System
Microsoft Windows 10	→	Microsoft Windows Twitter
UNIX	→	UNITwitter
XENIX	→	TwitterENITwitter
Linux	→	LinuTwitter
SpaceX	→	SpaceTwitter
XVIDEOS	→	TwitterVIDEOS
UI/UX	→	UI/UTwitter
Chromebook X	→	Chromebook Twitter
X JAPAN	→	Twitter JAPAN
C++	→	CTwitterTwitter

...and please open an issue, so you can notify me of another thing named including X, 10, 十, +, $\times$, *, or analogues of X.

A: "I want to install the X Window System for my Microsoft Windows 10 PC to improve UI/UX. How can I do that?"
B: "I think you don't need to install an extra window system, but you can enable Windows Subsystem for Linux, which was introduced in Windows 10."
A: "Thanks. I'll try that. By the way, I overheard you've visited SpaceX's headquarters and gone to X JAPAN's concert."
B: "Yes, I need relaxation. Those events made me so excited. How about we hang out sometime? I've reserved the presentation performance of the new Chromebook X."
A: "Too great! ......but sorry, I need to finish my C++ homework. I am writing some code for x86."
B: "OK. Good luck with your homework. I'll find someone else on X (formerly Twitter) to go to the event."

↓ ↓ ↓ ↓ ↓

Twitter:

A: "I want to install the Twitter Window System for my Microsoft Windows Twitter PC to improve UI/UTwitter. How can I do that?"
B: "I think you don't need to install an eTwittertra window system, but you can enable Windows Subsystem for LinuTwitter, which was introduced in Windows Twitter."
A: "Thanks. I'll try that. By the way, I overheard you've visited SpaceTwitter's headquarters and gone to Twitter JAPAN's concert."
B: "Yes, I need relaTwitteration. Those events made me so eTwittercited. How about we hang out sometime? I've reserved the presentation performance of the new Chromebook Twitter."
A: "Too great! ......but sorry, I need to finish my CTwitterTwitter homework. I am writing some code for Twitter86."
B: "OK. Good luck with your homework. I'll find someone else on Twitter (currently X) to go to the event."