Blăck'-jăck, n.
n. 1. A mineral, called also false galena. It is an ore, the sulphuret of zinc, consisting of sulphur, zinc, and a little iron; zinc-blende.
Sense 2. A leathern cup or can for beer. [Obs.]
There's a Dead-sea of drink i' the cellar, in which goodly vessels lie wrecked; and in the middle of this deluge appear the tops of flagons and black-jacks, like churches drowned i' th' marshes. Beau. & Fl.
Sense 3. (Bot.) The Quercus nigra, or barren oak.