sumac

1. (transitive) To apply a preparation of sumac to (an object), for example, to a piece of leather to tan it.Examples: "After this operation, the goods muſt be winched and well planked, or otherwiſe cleaned; they are then, according to the quality of them, to be ſumached, and then ſnitchelled off, and waſhed."; "Then lot 1 will be shumacked first time; that is, passed through a decoction of shumac, then through copperas, and then washed off, and if the decoction of shumac is kept up strong, after being all of them once shumacked they may be dried. [...] If the black liquor and the shumacking were powerful, some of them will shew themselves finished when dry."; "A great variety of Blue Drabs can be dyed by first Sumaching the cotton, and then in another tub add a little Nitrate of Iron or Copperas liquor, and give a few turns."transitive