Gall on tree — fine to eat a fruit

WordNet Word definitions in WordNet
n. oak gall caused by larvae of a cynipid wasp

Wiktionary Word definitions in Wiktionary
alt. oak gall#English. n. oak gall#English.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Oak \Oak\ ([=o]k), n. [OE. oke, ok, ak, AS. [=a]c; akin to D. eik, G. eiche, OHG. eih, Icel. eik, Sw. ek, Dan. eeg.] (Bot.) Any tree or shrub of the genus Quercus . The oaks have alternate leaves, often variously lobed, and staminate flowers in catkins. ...

Wikipedia Word definitions in Wikipedia
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak . Oak apples range in size from 2–5 cm in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp ...