Semi-basement is architectural term for a floor of a building that is half below ground, rather than entirely such as a true basement

Basement

__FORCETOC__A basement is one or more floors of a building that are either completely or partially below the ground floor. Basements are typically used as a utility space for a building where such items as the furnace, water heater, breaker panel or fuse box, car park, and air-conditioning system...

 or cellar

Basement

__FORCETOC__A basement is one or more floors of a building that are either completely or partially below the ground floor. Basements are typically used as a utility space for a building where such items as the furnace, water heater, breaker panel or fuse box, car park, and air-conditioning system...

.

Traditionally semi-basements were designed in larger houses where staff are kept. A semi-basement usually contained kitchen

Kitchen

A kitchen is a room or part of a room used for cooking and food preparation.In the West, a modern residential kitchen is typically equipped with a stove, a sink with hot and cold running water, a refrigerator and kitchen cabinets arranged according to a modular design. Many households have a...

s and domestic offices. The advantage over a basement is that a semi-basement is lighter as it can have windows, albeit interior windows that are often too high to enjoy a view. Historically this was an advantage as the servants, who traditionally inhabited such a floor, would not have the opportunity to waste time by looking out of the window.

The feature also has the aesthetic value of raising the ground floor, containing the building's reception rooms higher from the ground in order that they could enjoy better views, and be more free from the damp problems which always arose before the days of modern technology.

Today, London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 estate agents when selling former servant's rooms as modern apartment

Apartment

An apartment or flat is a self-contained housing unit that occupies only part of a building...

s often refer to the semi-basement as the "garden floor".