Hymen

[Vania]

A membrane which partially closes the opening of the vagina and whose presence is traditionally taken to be a mark of virginity.

[Luis Fok]

The hymen or vaginal corona is a tissue, usually doughnut-shaped, inside the vagina. They dont break or bleed, but some of the hymen can stretch or tear. It is normal for some of the hymen to wear away due to normal activities such as bathing, masturbation, even just moving around or stretching. Contrary to popular belief, it is actually pretty unlikely that a hymen will be damaged by [riding a bike] or a horse, because all these activities really do is put [pressure on] the [perineum], not interfere with the vagina itself. It does not completely cover the vagina; if it did, menstruation would be impossible for girls with intact hymens. By the time full [PVI] occurs, the hymen is (usually) already mostly worn away.

[Dave Paprocki]

A thin, elastic membrane stretched partly or completely across the entrance of the vagina ([vestibule]). It has no known biological function. An intact hymen has long and erroneously been considered the hallmark of female virginity . The presence or absence of the hymen is no proof of virginity or its opposite; the hymen can be broken in the normal course of physical activities when the body is stretched strenuously, as in athletics, sports or exercises. It may be absent, small, thin and [pliant], or, more rarely, tough and dense, completely blocking the [vaginal entrance]; it varies in size, shape and thickness from woman to woman . If it is too resistant to tearing it may require a small surgical incision, hymenotomy , or even removal, hymenectomy , before vaginal intercourse can take place .

[PussyCat]

a thin piece of skin that partly covers the opening to a persons vagina