Definition of dihedral in US English:



  • Having or contained by two plane faces.

    ‘a dihedral angle’
    • ‘In each test, we compared simulations guided by the wriggling algorithm to ones guided by a standard thrashing algorithm in which the dihedral angles are varied independently.’
    • ‘During the simulated-annealing simulations, changes in the dihedral angles are generated randomly for both side-chain and main-chain dihedral angles.’
    • ‘The 3D symmetries are identified by including dihedral angle information in the atom and molecular names so that two traversais match only if they are not only chemically equivalent but also conformationally equivalent.’
    • ‘If the right reflection matrix is added, the dihedral group D 6 can be made.’
    • ‘This difference is studied via contour plots of stacking probabilities as a function of the two central dihedral angles of the 3-atom linker.’


  • 1An angle formed by two plane faces.

    • ‘Bond distances, angles, and dihedrals, as well as the force constants, were taken for analogy with amino acids having similar functional groups (tyrosine and serine).’
    • ‘A reflectional symmetry is distinguished from a rotational symmetry by the fact that all dihedrals have their signs inverted, except for 180°, which is equivalent to 0°.’
    • ‘There is no significant difference in the number of trans conformations along the alkyl chain dihedrals in the presence of PCP.’
    • ‘Moreover, the fraction of stacked conformations for a given set of linker dihedrals is consistently greater for the bis-adenyl compounds than for the bis-naphthyl compounds.’
    • ‘Over the final 2000 steps of the protein minimization procedure, there were no restraints on side-chain dihedrals nor harmonic restraints on atomic positions.’
    1. 1.1Aeronautics Inclination of an aircraft's wing from the horizontal, especially upward away from the fuselage.
      Compare with anhedral
      • ‘Towing is much easier with a glider with dihedral.’
      • ‘Airplanes with high dihedral and the filler caps mounted far out on the wings won't show any level at all when there's still half-tanks aboard.’
      • ‘Further, given that dihedral diminishes gliding performance, its infrequent use suggests that a premium is placed on maximizing lift to drag ratio (that is, maximizing efficiency) during gliding.’
      • ‘This problem was countered by incorporating 15 degrees of dihedral in the horizontal tail, which initially had been virtually dead flat.’
      • ‘The first nine B - 25s had wings of constant dihedral, and - from personal experience - they were fun and very easy to fly, being extremely stable.’
    2. 1.2North American Climbing A place where two planes of rock meet at an angle of between 60° and 120°.
      • ‘The predominance of the cracks and dihedrals seemed to fall between hard 5.9 and straight-on 5.11, offering no moderate exit/escape, but late the first day I found a likely-looking ramp that seemed to lead to the top.’
      • ‘I then fought through a bush around an overhang, and then ran it out over a short slab to a small ledge at the base of an easy looking dihedral.’
      • ‘Leading the way, I arrive at a small tree that has somehow found a footing in the steep dihedral about seventy feet above the ground.’
      • ‘We meant to simply repeat his route, but several pitches up, where that route goes up and right into blocky cracks, we angled up and left into the obvious dihedral that shoots to the top of the wall.’
      • ‘The dihedral, a corner inset in the rock face, is going to be even trickier to down-climb, and if it starts to rain, we could be in trouble.’


Late 18th century: from di- ‘two’ + -hedral (see -hedron).