In small-arms weapons, the distance between the face of the bolt and the base of the cartridge when it is fully chambered and the bolt is locked
the empty space at the top of a sealed drum (or waste room) where flammable gases could concentrate
the volume left at the top of a filled container (bottle or jar or tin) before sealing
The area at the top of a vessel (fermenter, bottle, or keg) which does not contain any liquid In general, the goal is to minimize headspace, to prevent oxidation of the beer by oxygen in the air Headspace in the primary fermenter is not a serious concern, because the CO2 produced by fermentation forms a protective blanket on top of the beer, and forces nearly all of the oxygen out of the fermenter The headspace in a bottle is also sometimes referred to as ullage
The amount of space to leave at the top of a container to allow for expansion of food when frozen or processed
This is the empty space between the top of the beer and the top of the bottle after capping Note: an excessively large headspace means someone has been drinking the beer