In short: Apartament
Long: Some time ago I released a game called Resoraki, which is not an English word. Now I have decided to do the same. Apartament (Polish) = Apartment (English) <-- as you can see there is little difference, many people may not even see that the letter a should not be there.
Anyway, the correct title is, of course, "Apartament 1406", but You can use Apartment 1406.
Unfortunately, sometimes when I write Apartament auto-correction changes the word Apartament to English "Apartment". I will check the descriptions later to correct this.
The "Apartament" comes from... the French appartement meaning larger apartment, which in turn derives from the Italian appartare :P.