LOL!
On your suggestion, I looked up ‘thermospodium’. In Google Images, I saw something that looked like a modern day prepper’s ‘rocket stove’.
And then I found this:
COOKERY AND DINING IN IMPERIAL ROME, by Apicius:
https://archive.org/stream/cookeryanddining29728gut/29728.txt
Anyone who has the time will find this a very witty read - though perhaps not very useful for modern cookery. And: The Romans seemed to be into ‘fast food’.
The Hildesheim Roman Treasure, referenced in the book about Apicius, is beautiful:
-JT
From what I remember, a thermospodium was essentially a combination chaffing dish/samovar (food/drink) used in both kitchen and dining room.