The dihedral angle refers to the angle between two intersecting planes. There are several synonyms for this terminology, including torsion angle, twist angle, twist dihedral angle and simply angle. The torsion angle refers to the angle between two adjacent bonds in a molecule, whereas the twist angle is used in the context of twist angles in a twisted, nonplanar molecule. The twist dihedral angle is used in the context of helixes, while the simple term angle refers to the general geometrical orientation of two intersecting planes. Regardless of the specific term used, the dihedral angle is important in many fields, including chemistry, physics and engineering.