gel·se·mi·um \jelˈsēmēəm\noun Etymology: New Latin, modification of Italian gelsomino jasmine, from Arabic yāsamīn jasmine — more at jasmine 1.capitalized: a small genus of woody vines (family Loganiaceae) of Asia and the southern U.S. — see yellow jessamine 2.pluralgelsemiums\-mēəmz\orgelsemia\-mēə\: the root of the yellow jessamine formerly used in medicine