In science and engineering

Void (astronomy), the empty spaces between galaxy filaments
Lack of matter, or vacuum
Void, in boiling heat transfer, formed where there is a departure from nucleate boiling, causing a critical heat flux
Void, in mechanical engineering, is a bubble or pocket of vapor which forms near a propeller or pump, causing cavitation
Void, in injection molding, describes a defect where there are empty spaces (air pockets) in a completed part
Void coefficient, in nuclear engineering, is a measure of how spaces devoid of either moderator or coolant effect the reactivity of a nuclear reactor
Void ratio, of voids to solids in a mixture, in material sciences
Void safety, an issue raised in programming by a reference that is not attached to an object, also known as null reference
Void type, keyword indicating the absence of type information in many programming languages
VoiD (Vocabulary of Interlinked Dataset), the vocabulary to describe linked open datasets in order for users to discover, interlink and evaluate the quality of these datasets on the Web
Void - adjective describing a law which has no legal force or effect, or is not legally binding or enforceable