Definition of twinning in US English:



  • 1The bearing of twins.

    ‘the study showed an increased level of twinning in cattle’
    • ‘This result should reassure women planning pregnancies, their healthcare providers, and the wider health community that the evidence of an association between folic acid and an increase in twinning is probably false.’
    • ‘Increasing use of fertility drugs is almost certainly the main cause of the recent increase in dizygotic twinning in most developed countries.’
    • ‘Twins can result from a separation of the cells at the two-cell stage, but twinning can also occur in humans at a stage as late as 7 days of gestation, when the primitive streak has already started to form.’
    • ‘Bell had a deep interest in livestock breeding and tried to develop a strain of sheep with a high rate of twinning.’
    • ‘The other point has to do with the matter of identical twinning, which we are told can ‘happen up to six days after fertilization.’’
    • ‘Fraternal twinning - two fertilized ova becoming trapped inside a single shell - is a rare but well-documented occurrence in some birds.’
    • ‘The incidence of twinning is thus increased somewhat while the risk of triplets or quadruplets remains low.’
    • ‘The genetic associations were latent and intertwined with acquired factors, particularly with the degree of prematurity, birth order and twinning.’
    • ‘Gestation lasts approximately 7 months and single births are normal, though twinning does occur occasionally.’
    1. 1.1 The occurrence or formation of twinned crystals.
      • ‘Here also, twinning is referred to as ‘a mistake during the growth of a crystal.’’
      • ‘The name pentagonite was given to this mineral because of its twinning.’
      • ‘Finally we would like to mention that the understanding of the origin of twinning in a crystal can result in the discovery of better procedures to grow untwinned crystals.’
      • ‘Hexagonal bR crystals of space group P6 3 often exhibit a perfect hemihedral twinning.’
      • ‘Hemihedrally twinned crystals of bR were split along ab plane into parts of approximately the same thickness and it was demonstrated that each of them or at least one has no twinning.’