Having been cleaned with a vacuum cleaner; hoovered.

A lack of centralised political authority, especially following a conflict, revolution, change of power, etc.

plural of vacuum gauge

(physics) A vacuum having a pressure less than about a hundred millipascals

A bag used in vacuum cleaners to collect the dirt.

plural of vacuum bag

(cosmology) The disagreement of over 100 orders of magnitude between measured values of the vacuum energy density and the theoretical zero-point energy suggested by a naïve application of quantum field theory.

plural of vacuum aspiration

plural of vacuum desiccator

A non-return valve allowing atmospheric air into a boiler, if a cold boiler reduces its internal pressure on cooling down.