Occultation

Part of speech: noun

Pronunciation: /ˌɒkəlˈteɪʃ(ə)n/

Definitions

1. The process whereby one astronomical entity passes in front of another, resulting in the latter being momentarily hidden from observation
2. A situation in which an object is obscured from sight by another object that intervenes in the sightline from the observer's perspective
3. The act of one celestial body hiding another from view through a temporary alignment that disrupts direct observation

Etymology: The word "occultation" carries a meaning that has little to do with secrecy in the everyday sense. In astronomy, it describes the moment one body slides in front of another and blots it out, as when the Moon passes across the Sun during a solar eclipse. The Latin root "occultare" meant "to conceal, hide," and it gave English a family of words for things kept out of sight, from the mysterious to the magical. The term is built from "occult," itself from Latin "occultus," meaning "hidden," plus the suffix "-ation," which turns a verb-like idea into a noun for the act or process. So the word literally names the act of hiding. Latin "occultatio" also carried the sense of "concealment" and even "insinuation," a hint of something being implied rather than stated. Astronomers apply the term broadly. A star winked out by the Moon, or a planet passing behind a distant star, are both occultations, and timing them has long helped astronomers measure the sizes and paths of bodies in the sky.

Synonyms: eclipse, covering, obscuration