Lexic.us

¹ Source: wiktionary.com

Definition of Evection

1. irregularity in the moon's motion [n -S]

Medical Definition of Evection

1. 1. The act of carrying up or away; exaltation. 2. An inequality of the moon's motion is its orbit to the attraction of the sun, by which the equation of the center is diminished at the syzygies, and increased at the quadratures by about 1 deg 20'. The libration of the moon. Origin: L. Evectio a going up, fr. Evehere to carry out; e out + vehere to carry: cf. F evection. Source: Websters Dictionary (01 Mar 1998)

Lexicographical Neighbors of Evection

Literary usage of Evection

Below you will find example usage of this term as found in modern and/or classical literature:

1. History of the Inductive Sciences from the Earliest to the Present Time by William Whewell (1857)
"Ptolemy's Discovery of evection. BY referring, in this place, to the last-mentioned measure of the earth, we include the labours of the Arabian as well as ..."

2. The Moon: Her Motions, Aspect, Scenery, and Physical Condition by Richard Anthony Proctor (1873)
"... is called the evection, and is the only lunar perturbation which the ancient astronomers discovered. The discovery is commonly attributed to Ptolemy, ..."

3. An Introduction to Celestial Mechanics by Forest Ray Moulton (1914)
"The evection. It has just been shown that the eccentricity does not change in the long run; yet it undergoes periodic variations of considerable magnitude ..."

4. A Treatise on Astronomy by John Frederick William Herschel (1851)
"... on the Period and Dimensions of the disturbed Orbit— Variable Part of its Effect—Lunar evection—Secular Acceleration of the Moon's Motion—Invariability ..."

5. Rudimentary astronomy by Robert Main (1869)
"The first and largest of the inequalities thus discoverable by observation is called the evection, and was discovered by Ptolemy, having escaped the ..."

6. History of the Inductive Sciences: From the Earliest to the Present Times by William. Whewell (1837)
"Ptolemy's Discovery of evection. BY referring, in this place, to the last-mentioned measure of the earth, we include the labours of the Arabian as well as ..."

7. A Treatise on Astronomy by Elias Loomis (1868)
"These three inequalities, evection, variation, and annual equation, are the largest of the inequalities in the moon's motion. The other inequalities are ..."

Other Resources: