from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The condensed, inactive X-chromosome found in the nuclei of somatic cells of most female mammals. Also called sex chromatin.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A sex chromosome inactivated by packing in heterochromatin.
After Murray Llewellyn Barr (1908-1995), Canadian anatomist.(American Heritage® Dictionary of the English Language, Fourth Edition)