Triclinium vs cenaculum
So, what's the difference between the two?
What JimKillock wrote sounds good.
"dining-room" is interesting in an English-Latin dictionary from the 19th century.
The Oxford Latin Dictionary (modern) says basically what my first two links do, which are from Lewis and Short's Latin Dictionary (19th century). If you really want to see the OLD entries, I could photograph them for you (typing them out would be too difficult!).