<operating system> An operating system from IBM. According to IBM, it is a secure, scalable, high-performance enterprise operating system on which to build and deploy Internet and Java-enabled applications, providing a comprehensive and diverse application execution environment.
http://ibm.com/servers/eserver/zseries/zos/.
(2008-01-22)
Try this search on Wikipedia, OneLook, Google
Nearby terms: zorch « Zork « zorkmid « z/OS » zr » zsh » Z shell
