Definition: Synphyroid is a type of thyroid gland, characterized by its large size, dense texture, and characteristic coloration. It's often associated with thyroid disorders like hypothyroidism or hyperthyroidism, as well as other conditions such as polycystic kidney disease and autoimmune thyroid diseases. Synphyroid can be found in both males and females, but it tends to occur more frequently in women due to hormonal fluctuations that affect the thyroid gland's function.