Final answer:
A full-thickness thermal injury is known as a third-degree burn, which destroys the epidermis and dermis and often requires medical intervention such as skin grafting to heal.
Step-by-step explanation:
A full-thickness thermal injury refers to a type of burn that extends completely through the epidermis and dermis, reaching the underlying tissues. This type of burn is more commonly known as a third-degree burn. Third-degree burns destroy both the outer and inner layers of skin, causing nerve damage and often leaving the burned area without sensation. Unlike a first-degree burn, which only affects the epidermis and may result in temporary pain and redness, or a second-degree burn, which affects the epidermis and part of the dermis and may cause blisters, a third-degree burn requires immediate medical attention and may need surgical intervention such as debridement or skin grafting to heal.