of diseases, "incident to a whole people or region," 1660s, from Late Latin pandemus, from Greek pandemos "pertaining to all people; public, common," from pan- "all" (see pan-) + dēmos "people" (see demotic). Modeled on epidemic; OED reports that it is "Distinguished from epidemic, which may connote limitation to a smaller area." The noun, "a pandemic disease," is recorded by 1853, from the adjective. Related: Pandemia.
