Parlor
The parlor, in the USA, is indeed an archaic vestige of the olden days when a ceremonial room was needed, even in the smallest houses. In a city house, or a town house or row house, however you call it, this was usually the room at the front facing the street. It contained formal furniture, upholstered in black horsehair in Victorian times, a small center table, and a piano. Unless someone had to practice on the piano, it was entered only once a week, to dust. It was used only when the parson called, and for funerals, and therefore was not heated except on those occasions, the door being shut and the curtains drawn nearly all the time. In old neighborhoods hereabouts, this customs still survives. Old people still don't use the front room (which is generally what they call it now, although there are still some who call it the parlor) exacept to entertain visitors, even though they live in a house 9 feet wide with only 3 rooms and a kitchen on the ground floor.