Heard vendors in vaults (7)
I believe the answer is:
cellars
This might be a double definition.
'heard vendors' is the first definition.
Although both the answer and definition are plural nouns, I cannot see how one could define the other.
'vaults' is the second definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'in' is the link.
Can you help me to learn more?
(Other definitions for cellars that I've seen before include "Underground storage areas" , "Rooms below ground" .)