Australasian colloquial word meaning a break or rest from work. Frequently used in working-class work-places such as factories and construction sites. Originally refered to a cigarette-break (hence smoke-oh), but eventually refered to any rest or meal break.
Also used to describe food eaten during a break.
Also appended to other words to denote their association with a break from work;
eg; smoko shed, smoko room - the place where a break is held; smoko order - food ordered for smoko; smoko table &tc.
Now, ironically, frequently held in places where smoking is forbidden.