赤せき道どう

noun

equator

The great circle around the Earth, equidistant from the poles. Used in geography, climate, and everyday contexts.

• 赤せき道どう直ちょっ下かの国くに々ぐには一いち年ねん中じゅう暑あつい。

  Countries on the equator are hot all year round.

noun

celestial equator

The projection of the Earth's equator onto the celestial sphere. Used in astronomy; often specified as 天の赤道.

See also: 天の赤道

• 天てんの赤せき道どうは、地ち球きゅうの赤せき道どう面めんを天てん球きゅうに投とう影えいしたものです。

  The celestial equator is the projection of the Earth's equatorial plane onto the celestial sphere.