
1) Abnormal tree growth 2) Spongy tree gall 3) Tree gall
Found on
https://www.crosswordclues.com/clue/oak-apple

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 in the family Cynipidae. The adult female wasp lays single eggs in developing leaf buds. The w...
Found on
http://en.wikipedia.org/wiki/Oak_apple

(from the article `gall wasp`) The so-called oak apple, a round, spongy, fruitlike object about 2.5 to 5 cm (1 to 2 inches) in diameter, is caused by the larvae of the gall wasp ...
Found on
http://www.britannica.com/eb/a-z/o/1

Synonym for nutgall ... 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. ... Synonym: gall, galla, oak apple. ... (05 Mar 2000) ...
Found on
http://www.encyclo.co.uk/local/20973

Type: Term Pronunciation: ōk ap′ĕl Synonyms: nutgall
Found on
http://www.medilexicon.com/medicaldictionary.php?t=62008

[
n] - oak gall caused by larvae of a cynipid wasp
Found on
http://www.webdictionary.co.uk/definition.php?query=oak%20apple
noun oak gall caused by larvae of a cynipid wasp
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.