1. floors or levels of a building that are below the basement

Examples

• The office building has two subbasements for storage and mechanical equipment.
• Emergency generators are located in the subbasements of most hospitals.
• The parking garage extends three subbasements below street level.
• Water damage in the subbasements required extensive repairs.
• Security offices are often housed in the subbasements of government buildings.
• The museum’s rare artifacts are stored in climate-controlled subbasements.