evection

American  

[ih-vek-shuhn] / ɪˈvɛk ʃən /

noun

Astronomy.

1. a periodic irregularity in the moon's motion, caused by the attraction of the sun.

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evection British  

/ ɪˈvɛkʃən /

noun

1. irregularity in the moon's motion caused by perturbations of the sun and planets

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Other Word Forms

• evectional adjective

Etymology

Origin of evection

1650–60; < Latin ēvectiōn- (stem of ēvectiō ) a going upwards, flight, equivalent to ēvect ( us ) (past participle of ēvehere to carry forth, move forth) + -iōn- -ion

Example Sentences

This he called the evection, and introduced another epicycle to represent it.

From Kepler by Bryant, Walter W. (Walter William)

Here his mathematical powers are at their best, and he made a discovery of an inequality in the moon's motion known as the evection.

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck