What is another word for sub basement?
Pronunciation: [sˈʌb bˈe͡ɪsmənt] (IPA) 
The term "sub basement" refers to a level or space that is situated beneath the lowest point of a building's floor plan. Synonyms for this term include "lower level", "basement level", "cellar level", "subterranean level", and "underground level". These terms are often used interchangeably to describe any space that is located beneath ground level. Other terms that may be used to describe a sub-basement include "catacombs", "vaults", "tunnels", and "caverns". Regardless of the term used, sub-basements serve a variety of purposes such as housing mechanical equipment, storage facilities, or subterranean passageways connecting different buildings, making them an integral part of any structure.
