ep·i·de·mi·ol·o·gy (ěp'ĭ-dē'mē-ŏl'ə-jē, -děm'ē-) n. The branch of medicine that deals with the study of the causes, distribution, and control of disease in populations.
[Medieval Latin epidēmia, an epidemic; see epidemic + -logy.] ep'i·de'mi·o·log'ic (-ə-lŏj'ĭk), ep'i·de'mi·o·log'i·cal (-ĭ-kəl) adj., ep'i·de'mi·o·log'i·cal·ly adv., ep'i·de'mi·ol'o·gist n.