Final answer:
Exophthalmos is the term for a protrusion of the eyeballs in Graves' disease, also known as hyperthyroidism.
Step-by-step explanation:
The term for a protrusion of the eyeballs in Graves' disease is exophthalmos. Graves' disease, also known as hyperthyroidism, is an autoimmune disorder that affects the thyroid gland. In this condition, the immune system mistakenly attacks the thyroid gland, causing it to produce an excessive amount of thyroid hormones. One of the characteristic symptoms of Graves' disease is the bulging or protrusion of the eyeballs, known as exophthalmos.