Word of the Day – February 16, 2019

occultation

(ŏk′ŭl-tā′shən)

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.