In medicine, nodules are solid, elevated areas of tissue or fluid inside or under the skin with a diameter greater than 0.5 centimeters. Nodules may form on tendons and muscles in response to injury. The vocal cords may also develop nodules. Nodules are normally benign and often painless, although they can affect the functioning of the organ.
The sexual transmitted disease (STD) gonorrhea is also known for its cause of nodules on the genitalia and mouth for those who are victim to the disease.
Smaller (less than 0.5 cm) elevated soft tissue lesions may be termed papules.