| Abbreviation | Definition |
|---|---|
| WTD | Who To Delete |
| WUWA | Wake Up, We're Affected |
| WVPN | Wireless Virtual Private Network |
| WWAN | Wireless Wide Area Network |
| WWUI | World-Wide Unique Identifier |
| WYX | Boot Sector Virus |
| WYX.A | Boot Sector Virus |
| WYX.B | Boot Sector Virus |
| WYX.C | Boot Sector Virus |
| WYX.C1 | Boot Sector Virus |
| XACML | eXtensible Access Control Markup Language |
| XAV | XMAIL Anti-Virus |
| XAVF | XMAIL Anti-Virus Filter |
| XBL | Exploits Block List |
| XCB | eXtended CodeBook |
| XCBF | XML (Extensible Markup Language) Common Biometric Format |
| XI | Xtreme Integrity |
| XKM | XML Key Management |
| XKMS | XML Key Management Specification |
| XSRF | Cross-Site Request Forgery |