Definition of principal axis in English:

principal axis


  • 1Each of three mutually perpendicular axes in a body about which the moment of inertia is at a maximum.

    • ‘The principal axes of the moment of inertia tensor will be used to give us an idea of the overall rotation of the molecule.’
    • ‘In this case, the three sources of rotation can be oriented in two different ways with respect to one another - left-handed and right-handed - and the total spin is askew to the three principal axes.’
    • ‘Taking all these assignments into account, we can now calculate a rotational diffusion coefficient for the three principal axes of the inertia tensor, the two-tail vectors, the PN vector, and the intramolecular vector.’
    • ‘The rotation axis was the principal axis of the largest moment of inertia of the helix.’
    • ‘The relative lengths of the principal axes of the inertia tensor of I27 NHT are 1.0: 0.97: 0.42, thus indicating that cylindrical symmetry can be assumed.’
    1. 1.1
      another term for optical axis
      • ‘We suspect that the new species described here may be transitional between the two genera, because it contains spicules that are diagonal and others that are parallel to the principal axis.’
      • ‘After all, there is a large body of research showing that individuals find it easiest to recognize the intermediate or ‘canonical’ views of familiar objects that have a principal axis of elongation.’
      • ‘This specimen resembles those of Diagoniella cyathiformis because the skeletal net is composed of diagonally arranged stauractines and diactines, oriented at approximately 45° to the principal axis of the sponge.’
      • ‘The second is the orientation of the amino acid with respect to the principal axis of the other helix; the more the amino acid is directed toward the other helix, the better its burial.’
      • ‘It is not clear whether they evaluated these deviations along the principal axes or along an arbitrary reference frame.’