The phrase "guest quarters" refers to a designated space in a house or building that is specifically meant to accommodate visitors or guests. Full definition
Custom single level home with attached guest quarters featuring a separate entry, living room, large bedroom & bath with walk - in closet. (powayhomes.com)
Above: An expansive deck off the lower level guest quarters offers a cozy sitting area protected from the elements from the upper level patio. (onekindesign.com)
Above: The fully equipped kitchenette is part of the lower level guest quarters, complete with a dining area. (onekindesign.com)