A Marian apparition is an event in which the Blessed Virgin Mary

Blessed Virgin Mary (Roman Catholic)

Roman Catholic veneration of the Blessed Virgin Mary is based on Holy Scripture: In the fullness of time, God sent his son, born of a virgin. The mystery of the incarnation of the Son of God through Mary thus signifies her honour as Mother of God...

 is believed to have supernatural

Supernatural

The supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...

ly appeared to one or more people. They are often given names based on the town in which they were reported, or on the sobriquet

Sobriquet

A sobriquet is a nickname, sometimes assumed, but often given by another. It is usually a familiar name, distinct from a pseudonym assumed as a disguise, but a nickname which is familiar enough such that it can be used in place of a real name without the need of explanation...

 which was given to Mary on the occasion of the apparition. They have been interpreted in religious terms as theophanies

Theophany

Theophany, from the Ancient Greek , meaning "appearance of God"), refers to the appearance of a deity to a human or other being, or to a divine disclosure....

.

Marian apparitions sometimes are reported to recur at the same site over an extended period of time.