barr body

noun

1. a condensed, inactivated X chromosome present in most female mammals in the nuclei of all cells except the germ cells: used, as in sports competitions, to verify that an individual is genetically female.

n.

1. The condensed, inactive, single X-chromosome found in the nuclei of somatic cells of most female mammals and whose presence is the basis of sex determination tests that are performed, for example, on athletes.sex chromatin