Mouth sore, also known as canker sore or aphthous ulcer, is a common affliction that can cause discomfort while eating, talking, and brushing teeth. If you're searching for synonyms for mouth sore, you might consider using phrases such as oral ulcer, sore in the mouth, or lesion on the tongue. Another option is to use regional terminology such as a stomatitis, which is a mouth sore specific to the region surrounding the oral cavity. Other synonyms include a blister in the mouth, ulceration in the oropharynx, or mucosal lesion. Regardless of the words you choose, it's important to seek professional medical advice if mouth sores are persistent or frequently occurring.