Final answer:
The primary characteristic of Hodgkin's disease is painless, firm, and movable lymph nodes in the cervical area. This is a hallmark feature of Hodgkin's lymphoma, distinguishing it from other conditions with painful lymph node swelling.
Step-by-step explanation:
The primary characteristic of Hodgkin's disease, a type of lymphoma, in a 14-year-old child is most likely to be painless, firm, and movable lymph nodes in the cervical area. Hodgkin's disease is marked by the presence of characteristic Reed-Sternberg cells in the lymphatic tissue. The disease can present with various symptoms, including fever, weight loss, night sweats, and fatigue, but the hallmark feature that distinguishes Hodgkin's lymphoma is typically the presence of painless swollen lymph nodes, often in the neck area. Painful lymph nodes are more commonly associated with infections or other types of inflammations rather than Hodgkin's disease.