1. a small, painful ulcer or blister that forms inside the mouth, typically on the gums, tongue, or inner cheek
Usage: often used in the plural form 'aphthae'; medical/clinical term

Examples

• The aphtha on her tongue made eating spicy food uncomfortable.
• Multiple aphthae developed after she accidentally bit the inside of her cheek.
• Aphthae are common oral lesions that usually heal within one to two weeks.
• The dentist examined the aphtha and recommended a topical treatment.
• Stress and certain foods can trigger the formation of aphthae.