Short for eXtensible Markup Language, a new specification being developed by the W3C. XML is a pared-down version of SGML, designed especially for web documents. It enables designers to create their own customized tags to provide functionality not available with HTML. For example, XML supports links that point to multiple documents, as opposed to HTML links, which can reference just one destination each.
The group of files that reside on the domain host or nameserver. The zone file designates a domain, its subdomains and mail server.
I donít think there are many hosting terms starting with X and Z
Zend Encoder: encodes PHP scripts to protect your source codes from unauthorized copying/tampering
Zend Optimizer: allows faster execution of encoded PHP scripts
Zend Accelerator: provides optimization/caching of PHP scripts to enhance performance, increase number of concurrent requests handled, and decreases latency.