Frenchman welcomes romantic meeting in apartment (4-1-5)
I believe the answer is:
pied-a-terre
'apartment' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'frenchman welcomes romantic meeting' is the wordplay.
'frenchman' becomes 'pierre' (I've seen this before).
'welcomes' means one lot of letters goes inside another (in sense of 'invites in').
'romantic meeting' becomes 'date' (I've seen this before).
'pierre' going around 'date' is 'PIED-A-TERRE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for pied-a-terre that I've seen before include "Small home kept for occasional use" , "bijou accommodation" , "Lodging kept for occasional use (French)" , "Small secondary flat or house" , "Dwelling for occasional use" .)