bi·cy·clic \(ˈ)bī|sīklik, -|sik-\adjective alsobi·cy·cli·cal\-klə̇kəl\ Etymology: International Scientific Vocabulary bi- (I) + cyclic or cyclical 1.: consisting of or arranged in two cycles or circles < a bicyclic flower with the petals in two whorls > 2.: containing two usually fused rings in the structure of the molecule (as in naphthalene) < a bicyclic terpene >