Empty portion of a bottle

• Liquid amount lost in storage
• Unfilled part of a wine cask
• Amount needed to fill a cask
• Amount by which a cask falls short of being full
• To capacity, lid off, time for the remaining liquid
• Liquid lost from a container
• Amount of liquid lost in shipping

Wikipedia Word definitions in Wikipedia
Ullage (from the French ouillage ) is a winemaking term that has several meanings but most commonly refers to the headspace of air between wine and the top of the container holding the wine. It can also refer to the process of evaporation that creates the ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"amount by which a cask or bottle falls short of being full," late 15c., from Anglo-French ulliage (early 14c.), Anglo-Latin oliagium (late 13c.), Old French ouillage , from ouiller "to fill up (a barrel) to the bung," literally "to fill to the eye," from ...