An Etymological Dictionary of Astronomy and Astrophysics

The Sun’s apparent path in the sky relative to the stars in the course of a year. It is also the projection of the Earth’s orbital plane onto the → celestial sphere. Because of the inclination of the → Earth’s rotation axis, the ecliptic is tilted by about 23.4° with respect to the → celestial equator, an angle known as the → obliquity of the ecliptic. The ecliptic crosses the celestial equator at the → equinoxes.

Etymology (EN): From L. ecliptica linea “path of eclipses,” so called because eclipses happen only when the Moon is near this path, from eclipsis,
→ eclipse.

Etymology (PE): Hurpeh “sun path,” from hur “sun,” variant xor, cognate with Gk. helios, → Sun, + peh “path, way,” from O.Pers. paθi- “path, way;” Av. paθ-, variants paθi-, paθā-, pantay-;
Mid/Mod.Pers. pand “path, advice, councel;” Khotanese pande “road, path;” Ossetic fœndœg “path, road;”
cf. Skt. pánthā- “road, path, course;” Gk. patos “path, way;”
L. pons “bridge, path;” E. find; PIE base *pent- “to go, to tread.”