[vat] n [ME fat, vat, fr. OE faet; akin to OHG vaz vessel, Lith puodas pot] (13c) 1: a large vessel (as a cistern, tub, or barrel) esp. for holding liquors in an immature state or preparations for dyeing or tanning
2: a liquor containing a dye converted into a soluble reduced colorless or weakly colored form that on textile material steeped in the liquor and exposed to the air is converted by oxidation to the original insoluble dye and precipitated in the fiber
[2]vat vt vat.ted ; vat.ting (1784): to put into or treat in a vat