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Webster 1913 Edition

Noun.

A more or less round gall resembling a nut, esp. one of those produced on the oak and used in the arts. See

Noun.

An excrescence of the oak.

nutgall ‎(plural nutgalls)

A kind of gall on a tree formed in response to damage or parasite, with a nut-like shape.
- 1848, John Hannett, Bibliopegia, or, The Art of Bookbinding in all its branches, page 65:
  In two pints of water boil one ounce of tan, and a like portion of nutgall till reduced to a pint.