noun The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, such as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.
a vacuum of 26 inches of mercury, or 13 pounds per square inch
noun Ellipsis of vacuum cleaner.
noun A spacetime having tensors of zero magnitude.
noun A ground state of a quantum field or of local spacetime, or more abstractly the lowest-energy state of a system. A description of spacetime resulting from a particular compactification of spatial dimensions.
noun A description of spacetime resulting from a particular compactification of spatial dimensions.
noun An emptiness in life created by a loss of a person who was close, or of an occupation.
noun An exercise in which one draws their abdomen towards the spine.