large space; vast area
Refers to a physically large, open area, such as a hall, atrium, or expansive room.
A huge sculpture is displayed in the large space of this museum.
The station concourse is a large space and feels open.
Compound of 大 (だい, 'large') + 空間 (くうかん, 'space'). The reading だい becomes だい due to rendaku.