What term refers to the spread of a disease worldwide?

The term that refers to the spread of a disease worldwide is "pandemic." A pandemic is characterized by the global reach of an infectious disease, affecting a large number of people across multiple countries or continents. This distinction is important because it highlights the widespread impact of the disease beyond localized or regional outbreaks.

In contrast, an epidemic refers to a sudden increase in the number of cases of a disease in a specific area, but it does not imply that the disease is affecting populations on a global scale. An outbreak typically refers to a localized spike in cases, often within a community or specific population. Localized refers to diseases that are confined to a particular area and do not spread widely. Therefore, the correct answer emphasizes the global nature of a pandemic, distinguishing it from other terms that describe more confined occurrences of disease.