As nouns the difference between ullage and ulnage
is that ullage
is in a wine bottle, the empty space between the cork and the top of the wine while ulnage
is (legal|obsolete|uk) measurement by the ell.
In a wine bottle, the empty space between the cork and the top of the wine.
In a cask or barrel, the empty space, occupied by air, that is created by not completely filling the cask or barrel
The topping-up of such a barrel with fresh wine
In an industrial setting, the empty space in a tank, such as for fuel
(legal, obsolete, UK) measurement by the ell