A conventional art and design term for the empty or open space around, between, or enclosed by solid forms in a composition.
Negative space is a conventional term for open or empty space around, between, or enclosed by the solid elements of a composition. In sculpture, such spaces may be exterior intervals between masses or interior openings that pass through or are enclosed by the work.
These spaces can contribute decisively to silhouette, rhythm, balance, visual movement, and the legibility of the sculptural mass. Getty’s Art & Architecture Thesaurus defines negative space as an enclosed empty space in architecture, sculpture, or painting that makes an essential contribution to the composition.
Etymology
A modern English art-theory compound formed from negative + space.
Sculptor Notes
The word negative can be misleading if it suggests that space is secondary or merely what remains after the solid is made. In sculpture, space can be active, shaped, directed, compressed, opened, and composed as deliberately as mass. Where greater precision is needed, terms such as space, spatial interval, void, or notional space may be preferable.
References
https://www.getty.edu/vow/AATFullDisplay?subjectid=300056295