apparition

An act of becoming visible; appearance; visibility.

the sudden apparition of the Spaniards

The apparition of Lawyer Clippurse occasioned much speculation in that portion of the world.

The thing appearing; a visible object; a form.

[…] which apparition, it seems, was you.

An unexpected, wonderful, or preternatural appearance; especially, one by a ghost, phantom, or suchlike; the entity itself.

The region's economy is buoyed by tourism driven by past apparitions of the Virgin Mary.

The attic is said to be haunted by the ghostly apparition of a young girl who died there.

The first appearance of a star or other luminary after having been invisible or obscured; opposed to occultation.

A period of consecutive days or nights when a particular celestial body may be observed, beginning with the heliacal rising of the body and ending with its heliacal setting.