Main Entry: ul·lage

Pronunciation: \ˈə-lij\

Function: noun

Etymology: Middle English ulage, from Anglo-French ulliage, from *ullier to fill a partially empty cask, from Old French (Picard dial.) oel bunghȯle, literally, eye, from Latin oculus eye — more at eye

Date: 15th century

: the amount that a container (as a tank or cask) lacks of being full