crown gallDefinition of crown gall noun [mass noun] a bacterial disease of plants, especially fruit bushes and trees, which is characterized by large tumour-like galls on the roots and lower trunk. This disease is caused by the soil bacterium Agrobacterium tumefaciens [count noun] a large tumour-like gall caused by crown gall disease. crown gall in other Oxford dictionaries Definition of crown gall in the US English dictionary
