| Abbreviation | Definition |
|---|---|
| XHF | Xtreme Hardcore Federation |
| XHL | XBOX Hockey League |
| XHL | Xtreme Hockey League |
| XHW | Xtreme Hardcore Wrestling |
| XIW | Xtreme Impact Wrestling |
| XJW | X-treme Junkyard Wrestling |
| XKW | Xtreme Kronik Wrestling |
| XL | Xtra Large |
| XLC | Xtreme Launch Coaster |
| XM | X Matches |
| XMA | Xtreme Martial Arts |
| XMC | Xtreme Mountain Club |
| XMW | Extreme Midget Wrestling |
| XMW | Xtreme Mahnomen Wrestling |
| XMW | Xtreme Malden Wrestling |
| XMX | Xtreme Motocross |
| XMX | Xtreme MotoX |
| XNA | X-Treme Network Architecture |
| XNA | X-Treme Neurotic Assassins |
| XNG | Xtreme Northwest Gamers |