cervix

US /ˈsɝː.vɪks/
UK /ˈsɝː.vɪks/
"cervix" picture
1.

the narrow necklike passage forming the lower end of the uterus

:
During childbirth, the cervix dilates to allow the baby to pass through.
A Pap test is used to screen for abnormal cells in the cervix.