X86 :
A family of CPU's that include Pentium, Celeron and Athlon. Many different Operating Systems run on machines built around the x86 processor.
XHTML :
Stands for eXtensive Hyper Text Markup Language, and is a cleaner, stricter version of HTML. It is a proper subset of XML.
XML :
Stands for eXtensive Mark up Language. A type of web design code that can be used for news feeds and WAP websites.