EBV, or Epstein-Barr virus, is a member of the herpesvirus family and is primarily known for causing infectious mononucleosis. It is clinically significant as it is associated with various malignancies, including Hodgkin lymphoma and nasopharyngeal carcinoma, and can lead to complications such as splenic rupture. Understanding EBV's role in these conditions is crucial for diagnosis, management, and patient education in clinical practice.