Final answer:
Pemphigus is characterized by the presence of vesicles and bullae as oral lesions, which are fluid-filled blisters, with bullae being larger than vesicles.
Step-by-step explanation:
The characteristic oral lesion(s) of pemphigus are vesicles and bullae. Pemphigus is an autoimmune disorder that affects the skin and mucous membranes and is known for causing blisters and erosions on the skin and mucosal surfaces. The primary lesions are vesicles and bullae; vesicles are small fluid-filled blisters while bullae are larger blisters measuring at least 5 mm in diameter. These lesions typically rupture, leading to painful erosions that may become infected or spread.