Earth & SkyGreek → English
Ecliptic
/ɪˈklɪptɪk/noun
The apparent path of the Sun across the sky over a year, and the plane of Earth's orbit.
The Greek roots
ἐκ
ek
out of
λείπω
leípō
to leave, fail
Literally: “the failing-out circle”
The story of the word
Greek astronomers called it ὁ ἐκλειπτικὸς κύκλος, the circle where the failings happen, because eclipses occur only when the Moon crosses this line. The Moon's own orbit is tilted about five degrees off it, which is why we do not get an eclipse every month. λείπω, to leave off, also gives the ellipse, a conic section that falls short of a circle.
- How it travelled
- Ancient Greek → Late Latin → English
- First recorded
- 14th century
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
Same family
eclipseellipseellipticaleleison
In a sentence
The planets never stray far from the ecliptic, which is why they all rise along the same track.