Zarf
No, this isn’t the East London pronunciation of South, though it is close! A zarf is actually …
A holder, usually of ornamental metal, for a coffee cup without a handle to protect the cup and also the fingers of the drinker from the hot liquid.
The zarf was originally often made from metal — silver, gold, copper and brass being the most usual choices. However zarfs were also made of wood, ivory, bone, horn, or tortoiseshell.
In modern times they are the, usually cardboard, sleeves which coffee shops put round your paper cup of take out coffee — although coffee shop chains don’t usually call them zarfs, but cup-sleeves or something similar.
Oh and the word comes from the Arabic word zarf, meaning meaning a container or envelope.