Aphthous ulcers are known as -
Aphthous ulcers 

Also known as Canker Sores
These are superficial Ulcerations of the oral mucosa.
The lesions may be Single or multiple.
Ulceration is surrounded by an erythematous halo and is Covered by a thin exudate.
Canker sores
Marjolin's ulcer
Curling's ulcer
Cushing ulcers