'3.5 bedroom apartment': What are half rooms in Switzerland?

[BECKHAM]

Whether you have recently moved to Switzerland or are hunting for a new apartment, chances are you have seen 1.5 or 3.5-room flats advertised online. But what is a half room?

for more... (https://www.thelocal.ch/20230609/3-5-bedroom-apartment-what-are-half-rooms-in-switzerland)