What term describes the appearance of the fetus's head at the vaginal opening during labor?

Crowning refers to the moment during labor when the top of the fetus's head becomes visible at the vaginal opening. This occurs toward the end of the second stage of labor, indicating that the baby is descending and will soon be delivered. It is an important stage because it signifies that the birth is imminent and that healthcare providers need to be prepared for the delivery.

Engagement is the term used to describe the stage when the fetal head enters the pelvic inlet, but it does not imply visibility at the vaginal opening. Effacement refers to the thinning and shortening of the cervix, which prepares the body for delivery, but it is not directly related to the appearance of the fetus's head. Dilation refers to the opening of the cervix during labor, but again, does not describe the fetal head's visibility in the vaginal canal.