The term appearance, from the Latin word apparitio, alludes to act and consequence of appearing: make yourself present, reveal yourself. The concept has several uses according to the context.
In its most elemental sense, an apparition implies that something or someone manifests or lets itself be seen. For example: "The appearance of whales near the beaches of the north of the city surprised biologists, since it is not usual for these animals to move around the area", "Numerous human rights organizations marched to the Government House to demand the appearance alive of the militant who has not been seen for three days", "The residents of the neighborhood were surprised by the appearance of posters with fascist proclamations on the public highway".
Another meaning of appearance refers to the vision of a fantastic or supernatural creature, a spiritual entity or a ghost. This vision can occur in different ways and depends on the sensation, perception or belief of the person: "Yesterday, while walking through the forest, I had an apparition: I saw the Virgin Mary under a tree", "The religious claimed to have had several appearances of angels in the temple", "I would love to have an appearance from my grandfather to ask him what happens after death ...".
In the field of religion, the appearances usually include revelations. Among the most mentioned are the marian apparitions, which occur when the Virgin mary it shows. Of course, the way of understanding or accepting this type of apparition is associated with the faith.