ounces,particularly of crack

Operating system. Simply, a program that runs your computer. Examples of an operating system are CP/M, DOS, Windows, Mac OS, Linux, and Palm OS, though there are many more. One will oftentimes become overly attached to their OS, preaching it as though it were a religion and shunning all who use anything even slightly different.

Abbreviation for Operating System

A good list of popular Operating Systems are listed here (taken from "www.bellevuelinux.org"):
AIX
Amiga
BeOS
Darwin
FreeBSD
FreeDOS
GNU/Hurd
HP-UX
IRIX
JavaOS
Linux
Mac OS X
Microsoft Windows
MINIX
MS-DOS
NetBSD
OpenBSD
Palm OS
QNX
SkyOS
Solaris
TRON
Tru64

An operating system is the main software that runs a computer, without an operating system a computer is almost useless.

There is no best operating system, they all have their advantages/disadvantages and were all developed with some kind of goal in mind.

abbreviation of "one's self" sometimes used in dictionaries

the opposite of so. when a conversation dies, instead of saying so, say os. it will jump the conversation to a new level to keep the flow.

A.K.A Original Sin

A clan in the popular mobile game Vampires Dark Rising or VDR for short. Founded by the Leader Antimus "Ant", they are an awesome group who treat each other like family and have beat Venom one of the largest clans after a year long war.