gall -
To cause pitting on a surface being cut from the friction between the two surfaces exceeding the bond of the material at a point.
Wikipedia
Galls are outgrowths on the surface of lifeforms caused by invasion by other lifeforms, such as parasites or bacterial infection. Plant galls are abnormal outgrowths of plant tissues and can be caused by various parasites, from fungi and bacteria, to insects and mites. Plant galls are often highly organised structures and because of this the cause of the gall can often be determined without the actual agent being identified.
OmegaWiki Dictionary
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gall A bitter brownish-yellow or greenish-yellow secretion produced by the liver, stored in the gallbladder, and discharged into the duodenum where it aids the process of digestion.