Definition of "apparition"

the sudden apparition of the Spaniards

1855–1858, William H[ickling] Prescott, History of the Reign of Philip the Second, King of Spain, volumes (please specify |volume=I to III), Boston, Mass.: Phillips, Sampson, and Company

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

1814 July 7, [Walter Scott], Waverley; […], volumes (please specify |volume=I to III), Edinburgh: […] James Ballantyne and Co. for Archibald Constable and Co.; London: Longman, Hurst, Rees, Orme, and Brown

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

1709 August 27 (Gregorian calendar), Isaac Bickerstaff [et al., pseudonyms; Richard Steele et al.], “Tuesday, August 16, 1709”, in The Tatler, number 55; republished in [Richard Steele], editor, The Tatler, […], London stereotype edition, volume I, London: I. Walker and Co.; […], 1822

I think it is the weakness of mine eyes / That shapes this monstrous apparition.

1599 (first performance), William Shakespeare, “The Tragedie of Iulius Cæsar”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene iii]

The heavenly bands […] a glorious apparition.

1667, John Milton, “Book X”, in Paradise Lost. […], London: […] [Samuel Simmons], […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873,

The apparition wobbled in front of Arthur's eyes, though the truth of the matter is probably that Arthur's eyes were wobbling in front of the apparition.

1982, Douglas Adams, Life, the Universe and Everything, page 24