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oc·cul·ta·tion (ŏkŭl-tāshən)
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n.
1. The act of occulting or the state of being occulted.
2. Astronomy
a. The passage of a celestial object across the line of sight between an observer and another celestial object, as when the moon moves between Earth and the sun in a solar eclipse.
b. The progressive blocking and unblocking of light or other electromagnetic radiation from a celestial source during such a passage: a lunar occultation of a quasar; a planetary occultation of a star.
c. An observational technique for determining the position or radiant structure of a celestial source undergoing such occultation or of the object causing the occultation.
3. Islam The temporary, supernatural removal of a holy person from visible existence, as Shiites believe is the case with the 12th imam.

[Middle English occultacion, from Latin occultātiō, occultātiōn-, from occultātus, past participle of occultāre, frequentative of occulere, to conceal; see OCCULT.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.