verglas
/ˈvɛːɡlɑː
/noun [mass noun]
A thin coating of ice or frozen rain on an exposed surface.The rocks were still wet, even coated with verglas in a few places, but it wasn't raining....
- A recent ice storm had coated the tree branches with a thin layer of verglas, which was now falling down all around me in chunks.
Origin
Early 19th century: French, from verre 'glass' + glas (now glace) 'ice'.