Cankers are small sores that form in the mouth or on the skin. While the term canker is widely used, there are many synonyms that can describe this painful condition. One of the most common synonyms is mouth ulcers, which refers specifically to canker sores that form in the mouth. Other synonyms include aphthae, stomatitis, and oral lesions. In the case of canker sores that form on the skin, synonyms might include skin ulcers, dermal sores, and lesions. Regardless of what terminology you use, cankers can be quite uncomfortable, causing pain and difficulty eating or speaking. Treatment may include topical agents, pain relief medications, or lifestyle modifications to reduce inflammation and promote healing.