Canker refers to a type of sore or ulcer that can develop on the skin or mucous membranes, often causing pain and discomfort. It is commonly associated with conditions like canker sores, which are small, painful lesions that appear inside the mouth. These sores can be triggered by stress, certain foods, or nutritional deficiencies. In plants, canker is a disease caused by various pathogens, including fungi and bacteria, leading to the death of plant tissues. Symptoms may include sunken lesions on stems or branches, which can hinder the plant's growth and overall health. Effective management often involves proper care and treatment to prevent the spread of the disease.