Nodules are discrete, palpable, solid lesions typically greater than 1 cm in diameter that can arise in various tissues due to inflammation, neoplasia, or fibrosis. Clinically, identifying nodules is crucial as they may indicate underlying pathology requiring further investigation, such as malignancy or granulomatous disease. For example, thyroid nodules are common and may represent benign adenomas or thyroid cancer, necessitating careful assessment and management.