occultation

Noun

occultation (countable and uncountable, plural occultations)

1. An astronomical event that occurs when one celestial object is hidden by another celestial object that passes between it and the observer when the nearer object appears larger and completely hides the more distant object.
   • [T]he diſtance of any place within this kingdom from it, will not much vary the manner of their Appearance in any of the Phænomena, except the Eclipſe of the Sun: for, in the Occultations, the Stars will appeare to paſs nearly under the ſame Angles and Spots of the Moon; […]1670 January 17, John Flamstead [i.e., John Flamsteed], “An Accompt of such of the More Notable Celestial Phænomena of the Year 1670, as will be Conspicuous in the English Horizon; Written by the...
   • The bright star Aldebaran is to be occulted by the moon on December 20th, at about 5 o'clock pm. Aldebaran is said to be eight hundred and eighty times the mass of the sun, with a diameter of over 8,000,000 miles; a distance so great that a meteor traveling at the rate of thirty miles per second...1904 December, Melville Dozier, “[Transactions for November. III. Meetings of Sections.] 2. Section of Astronomy”, in Bulletin of the Southern California Academy of Sciences, volume III, number 9...

   Synonyms:

   eclipse

2. The state of being occult (“hidden, undetected”).
   • If Mr. [Thomas] Campbell's poetry was of a kind that could be forgotten, his long fits of silence would put him fairly in the way of that misfortune. […] [T]he re-appearance of such an author, after those long periods of occultation, is naturally hailed as a novelty—and he receives the double...1825 January, [Francis Jeffrey, Lord Jeffrey], “Art. I. Theodric, a Domestic Tale: With other Poems. By Thomas Campbell. 12mo. pp. 150. London, 1824.”, in The Edinburgh Review, or Critical Journal...
   • In western Europe, the most celebrated instance of the occultation of a river was that of the Rhone, near Bellegarde, on the confines of France and Savoy, about 18 miles from Geneva; but, alas, on visiting this interesting spot in the autumn of 1855, I found that the Perte du Rhone no longer...1857 July, Thomas M. Traill, “On the Occultation of Rivers”, in Thomas Anderson, William Jardine, John Hutton Balfour, Henry D[arwin] Rogers, editors, The Edinburgh New Philosophical Journal...

   Synonyms:

   hiddenness, invisibility, occultness

3. (Shia) The disappearance of the Twelfth Imam, or Mahdi, who is believed alive and present in this world, but hidden until his reappearance at the end of time.
   • We are therefore, constantly hoping for the joy and happiness, personified in Imām al-Mahdi, the Imām who is alive at this very time, and who is himself awaiting the command of Allāh to reappear, so that he may strengthen the weak, and judge the oppressors. He will reappear "without having done...2002, Allamah Sayyid Saeed Akhtar Rizvi, Prophecies about Occultation of Imãm Al-Mahdi (A.S.), Dar es Salaam, Tanzania: Bilal Muslim Mission of Tanzania, →ISBN, page 7