What does 궤도(軌道) mean?

Here are the meanings of 궤도 (軌道) in my dictionary:

1. an orbit; a circle
2. a (railroad) track
3. a track (in the figurative sense)

The Chinese character 軌(궤) originally referred to the distance between the wheels of a cart, which could have been determined by measuring the distance between the tracks it left on a road. The character 軌(궤) is made up of the characters 車(cart) and 九(nine). Nine was a number that the Chinese also used to mean "many." The combination of the two characters, therefore, literally meant "many carts." Many carts following the same tracks would have left a fixed set of tracks on a road, which would have been hard to deviate from, especially if they were deep tracks. Since the character 道 (도) means "road," 궤도 essentially means a "tracked road."

I assume that the idea of "orbit" developed from the fact that the tracks on a road are equal distance from each other, just as an orbiting object in space would be from the surface of the earth.

Here are the expressions my dictionary gave for 궤도.

• 궤도 기중기 -- a gantry (crane)
• 궤도면 -- a plane of orbit
• 궤도를 벗어나다 -- go out of orbit
• 궤도 부설 -- track construction
• 궤도 비행 -- an orbital flight
• 궤도 속도 -- an orbital velocity
• 궤도 운동 -- an orbital motion
• 궤도에 오르다 -- be started along the right lines
• 궤도에 올라 있다 -- be well under way
• 궤도에 올리다 -- set (a business corporation) on its way
• 궤도 체류 연수 -- orbital life
• 궤도축 -- the axis of an orbit
• 궤도 표시기 -- a track indicator
• 극궤도 -- a polar orbit
• 단선 궤도 -- a single track
• 달 궤도 -- a lunar orbit
• 대기 궤도 -- a parking orbit
• 복선 궤도 -- a double railroad track
• 위성을 궤도에 올려놓다 -- put a satellite into orbit
• 위성의 궤도를 수정하다 -- adjust the orbit of a satellite
• 원궤도 -- circular orbit
• 인공 위성이 궤도에 올랐다 -- The satellite has gone into orbit.
• 전기 궤도 -- an electric tramway
• 전위 궤도 -- transfer orbit
• 정지 궤도 -- a geostationary orbit
• 주기 궤도 -- a synchronous orbit
• 지구 궤도 -- the earth's orbit
• 타원 궤도 -- the elliptic orbit
• 편심 궤도 -- an eccentric orbit