- An excrescence on the oak, Quercus infectoria (family Fagaceae) and other species of Quercus, caused by the deposit of the ova of a fly, Cynips gallae tinctorae; an astringent and styptic, by virtue of the tannin it contains. SYN: gall (3), galla, oak apple.
* * *nut·gall 'nət-.gȯl n a gall that resembles a nut esp a gall produced on an oak (esp. Quercus infectoria) and used as a source of tannic acid
* * *nut·gall (nutґgawl) [L. galla] an excrescence growing on oak trees (genus Quercus), especially Q. alba (the white oak), produced by insect eggs and larvae embedded in the plant tissues; it is a source of gallic and tannic acids, which are used in various pharmaceuticals for their astringent properties. Called also gall, Aleppo gall, and gallnut.
Medical dictionary. 2011.