[fra.ter.nal] adj [ME, fr. ML fraternalis, fr. L fraternus, fr. frater brother--more at brother] (15c) 1 a: of, relating to, or involving brothers b: of, relating to, or being a fraternity or society "a ~ order"
2: derived from two ova: dizygotic "~ twins"
3: friendly, brotherly -- fra.ter.nal.ism n -- fra.ter.nal.ly adv