[ok-uhl-tey-shuh n]


Astronomy. the passage of one celestial body in front of another, thus hiding the other from view: applied especially to the moon's coming between an observer and a star or planet.
disappearance from view or notice.
the act of blocking or hiding from view.
the resulting hidden or concealed state.

Origin of occultation

1375–1425; late Middle English < Latin occultātiōn- (stem of occultātiō) a hiding, equivalent to occultāt(us) (past participle of occultāre to conceal, keep something hidden, frequentative of occulere; see occult) + -iōn- -ion
Related formspre·oc·cul·ta·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for occultation

Historical Examples of occultation

  • On this evening there was to be an occultation of a star at the moon's dark limb.

  • The disappearance of a star by the interposition of the moon is called an "occultation."

  • The phenomenon illustrated is called the "occultation" of the planet.

    The Story of the Heavens

    Robert Stawell Ball

  • I was, in particular, struck with the effect of the occultation of Principle on motives.

    The Monikins

    J. Fenimore Cooper

  • An occultation of Mercury by Venus was observed with a telescope on May 17, 1737.

British Dictionary definitions for occultation



the temporary disappearance of one celestial body as it moves out of sight behind another body
the act of occulting or the state of being occulted
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for occultation

early 15c., "disguise or concealment of identity," from Latin occultationem (nominative occultatio), noun of action from past participle stem of occultare "to hide, conceal," frequentative of occulere (see occult).

Online Etymology Dictionary, © 2010 Douglas Harper

occultation in Science



The passage of one celestial object in front of another, temporarily blocking the more distant object from view. Occultations can provide information about the existence and measurements of the obscuring object. For example, when an asteroid passes in front of a star, the star is temporarily obscured to an observer on Earth, thus revealing the presence and approximate size of the asteroid. In 1977, astronomers were able to identify the rings around the planet Uranus when the otherwise invisible rings were observed to occult a background star. Occultations have also led to the discovery of more distant objects in space, such as binary stars and extrasolar planets. Compare transit.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.