Noun | 1. | hyperparathyroidism - excessive secretion of parathyroid hormone resulting in abnormally high levels of calcium in the blood; can affect many systems of the body (especially causing bone resorption and osteoporosis) adenosis, gland disease, glandular disease, glandular disorder - a disorder of the glands of the body hypoparathyroidism - inadequate secretion of parathyroid hormone resulting in abnormally low levels of calcium in the blood |