Meaning of neural tube defect

neu'ral tube' de"fect

Pronunciation: [key]
— Pathol. Pathol.
  1. any of a group of congenital abnormalities involving the brain and spinal cord, including spina bifida and meningocele, caused by failure of the neural tube to close properly during embryonic development.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.