Round, lidded container made of copper or brass, with long wooden, iron or brass handle. The pan held hot coals or charcoal - or later water - and were used to warm beds. It became popular in the 16thC but was replaced in the 19thC by metal or stoneware hot-water bottles. Most later examples were purely decorative.
Warming-pan is slang for a person who temporarily hold's or reserves another's place.
[n] - a long-handled covered pan holding live coals to warm a bed
long-handled covered pan holding live coals to warm a bed.
noun a long-handled covered pan holding live coals to warm a bed