Definition of teratology in US English:

noun

• 1Medicine Biology
  The scientific study of congenital abnormalities and abnormal formations.

  Example sentences

  • ‘Rejecting the notion that freaks were sports of nature, Saint - Hilaire argued that teratology (the medical study of congenital monstrosity) should link normal and abnormal development.’
  • ‘It is also forging links with medically oriented areas of developmental biology such as teratology and endocrine disruption.’
  • ‘Genomics is unlikely to be of use in teratology studies because of the rapid rate of change in the developing organism.’

• 2Mythology relating to fantastic creatures and monsters.