| Abbreviation | Definition |
|---|---|
| XA | Xtreme Assassins |
| XAK | X-Treme Ass Kickers |
| XBBL | Xperimental Blood Bowl League |
| XBH | Extra Base Hits |
| XBS | Xtremes- Beyond Sport |
| XBW | Xtreme Backyard Wrestling |
| XC | Cross Country |
| XC | eXtreme Cruiserweight |
| XCC | XelaSoft Control Center |
| XCW | eXtreme Championship Wrestling |
| XD | eXtra Damage |
| XDC | Xander Dance Club |
| XDC | Xtreme DirtCars |
| XDC | Xtreme DirtCars, Inc. |
| XDF | Xcessive Delta Force |
| XDI | Xtreme DirtCars, Inc. |
| XDW | Xcessive Delta Force Warrior |
| XDW | Xtreme Deathmatch Wrestling |
| XDW | Xtreme Domination Wrestling |
| XDZ | Xtreme Danger Zone |