What is Sacking ?
Sacking is (noun) 1. dismissal from a job The union protested against the sack- ings. (NOTE: The plural is sackings.) 2. coarse material from which sacks are made Hemp is used to make ropes and sacking. (NOTE: no plural) 3. old sacks There’s a heap of sacking over there in the corner of the warehouse. (NOTE: no plural)
source: Easier English, Student Dictionary Upper Intermediate Level