From Longman Dictionary of Contemporary Englishflysheetfly‧sheet /ˈflaɪʃiːt/ (also fly) noun [countable] DLOa sheet of material that is put over a tent to protect it from the rain
Examples from the Corpus
flysheet• Ventilation: ample room between inner and flysheet for air to circulate, especially when doors at either end are open.• The front bellend uses an extra hooped pole which extends the flysheet forward giving ample room for storage.• A third pole is inserted into the front of the flysheet to extend the bell end.• Zips: one curved L-shaped zip on the flysheet and three zips on the inner door.• To improve the water resistant performance the flysheet seams can be sealed.• Two side guylines are then pegged out to secure the flysheet.• The flysheet is silicone protected on both sides, something that not many manufacturers do.• The flysheet zips are protected by a small weather flap. 