gall¹ / gôl/ • n. 1. bold, impudent behavior: the bank had the gall to demand a fee.2. the contents of the gallbladder; bile (proverbial for its bitterness). ∎  an animal's gallbladder. ∎  used to refer to something bitter or cruel: accept life's gall without blaming somebody else.gall² • n. 1. annoyance; irritation: he imagined Linda’s gall as she found herself still married and not rich.2. (esp. of a horse) a sore on the skin made by chafing.• v. [tr.] 1. make (someone) feel annoyed: he knew he was losing, and it galled him.2. make sore by rubbing: the straps galled their shoulders.gall³ • n. an abnormal growth formed on plants and trees, esp. oaks, in response to the presence of insect larvae, mites, or fungi. ∎  [as adj.] denoting insects or mites that produce such growths: gall flies.

gall (cecidium) An abnormal growth or swelling in a plant. The formation of a gall may be induced by infection of the plant with bacteria or fungi, or by attack from certain mites, nematodes, or insects. Galls may be formed on roots, stems, or leaves. Some galls (e.g. clubroot and crown gall) are symptoms of disease; others appear to do little harm to their hosts, while some may actually be beneficial to the plant (e.g. nitrogen-fixing root nodules of legumes). Galls are variously structured, ranging from a simple outgrowth to a large and histologically complex structure with up to 5 distinct tissue layers with nutritive zones. Most gall-forming species are members of the insect family Cynipidae (Hymenoptera), and often have complex, heterogynous life cycles, utilizing different parts of the same host or different hosts, which are generally Quercus species. The mechanism of gall initiation and development is little understood, and the study of galls offers an unparalleled opportunity for physiological and ecological research. The gall community supports a large number of parasitoids, hyperparasitoids, and inquilines (species which use the gall but do not kill its occupant).

gall(cecidium) An abnormal growth or swelling in a plant. The formation of a gall may be induced by infection of the plant with bacteria or fungi, or by attack from certain mites, nematodes, or insects. Galls may be formed on roots, stems, or leaves. Some galls (e.g. clubroot and crown gall) are symptoms of disease; others appear to do little harm to their hosts, while some may actually be beneficial to the plant (e.g. nitrogen-fixing root nodules of legumes). Galls are variously structured, ranging from a simple outgrowth to a large and histologically complex structure with up to five distinct tissue layers with nutritive zones. Most gall-forming species are members of the insect family Cynipidae (Hymenoptera), and often have complex, heterogynous life cycles, utilizing different parts of the same host or different hosts, which are generally Quercus species. The mechanism of gall initiation and development is little understood, and the study of galls offers an unparalleled opportunity for physiological and ecological research. The gall community supports a large number of parasitoids, hyperparasitoids, and inquilines (species which use the gall but do not kill its occupant).

gall (cecidium) An abnormal growth of a plant tissue or organ elicited by a foreign organism. Galls can take a wide variety of forms, but most frequently occur as swellings or pits in stems, roots, leaves, and buds. Organisms responsible for their formation include bacteria, viruses, fungi, nematodes, mites, and insects. The gall structure can be quite complex, with several distinct cell layers, or relatively simple and undifferentiated, but is typically very distinct from surrounding normal tissue and often is characteristic of the eliciting organism. It can involve cell enlargement (hypertrophy) and/or cell proliferation (hyperplasia). The mechanisms underlying gall formation are known in only a few cases. The bacterium Agrobacterium tumefaciens, which is responsible for crown galls, induces a genetic change in infected host tissue by transfer of a plasmid bearing tumour-forming genes. Insects may secrete substances in their saliva that induce gall formation, or in some cases may transmit viruses or other genetic carriers that affect the plant genome.

gall1 bile; bitterness. XII. — ON. gall, corr. to OE. ġealla, OS., OHG. galla (Du. gal, G. galle) :- Gmc. *ʒallam, *ʒallan-, -ōn, f. IE. *ghol- *ghel- (repr. by Gr. kholé, L. fel bile); cf. YELLOW.