ETYM A dialectic form for fat, Old Eng. fat, AS. faet.
1. A large cistern or tub, especially one used for holding fluids involved in some process, such as beer-making, tanning, etc.
2. A measure for liquids, and also a dry measure; especially, a liquid measure in Belgium and Holland, corresponding to the hectoliter of the metric system.

Value Added Tax, A tax levied on the difference between a commodity's price before taxes and its cost of production; Also called: value-added tax, ad valorem tax.

To put into or treat in a vat.