The Collaborative International Dictionary
Gallnut
Gallnut \Gall"nut`\, n. (Zo["o]l.) A round gall produced on the leaves and shoots of various species of the oak tree. See Gall, and Nutgall.
Wiktionary
gallnut
n. slight protuberance on a tree, caused by insects
Usage examples of "gallnut".
When it is warm, powdered gallnuts and iron filings should be added to it, and the whole should be warmed again.
The liquid is then painted on to the teeth by means of a soft feather brush, with more powdered gallnuts and iron, and, after several applications, the desired colour will be obtained.
To get the ants they'd have to buy our cree and, inasmuch as they'd have to use the ant eggs to get the gallnuts to make the formula to turn their cree blue,' Amherst drew a long breath, 'the ants couldn't reproduce.