The USS Enterprise in orbit of an Earth-like planet
Nimbus 1 in polar orbit
Orbit is a term used to describe the flight path of an object in space which has a repetitive motion and has a distinct center with respect to its flightpath.
A starship uses a form of orbit to maintain its relative position. The term orbit is also used to define the flight path of a planet within its own solar system. (TNG: "Force of Nature")
In 2269, Spock detailed to Abraham Lincoln that the USS Enterprise was 643 miles, 2,021 feet, 2.04 inches above the surface of Excalbia. (TOS: "The Savage Curtain")
There are several forms of orbit; some of them are referred to by Starfleet personnel with names like "standard orbit" or "high orbit."
- Synchronous orbit: This form is used by a starship to maintain position towards a specific point on a planet's surface. The ship's velocity will be the same as the rotation speed of the planet. (TNG: "Relics")
- High orbit: A form of orbit in which the starship maintains a large distance from the planet's surface for safety reasons but is still close enough to use the transporter. (VOY: "Ex Post Facto", "The Omega Directive") The USS Voyager parked in high orbit over Earth, when it visited the planet in 1996, at an altitude of 20,000 kilometers. (VOY: "Future's End")
- Polar orbit: A type of spacecraft orbit that passes within 22,300 miles of the geographic poles of a planet. An image of the Nimbus 1 satellite in polar orbit of Earth was seen in the USS Enterprise library computer. (TOS: "The Cage")
- It is safe to assume that standard and high orbit are nothing more a form of synchronous orbit with a set of predefined speed and altitude parameters.
Terok Nor (later Deep Space 9), was in synchronous orbit of Bajor during the Occupation. (DS9: "Emissary", "Necessary Evil", "Wrongs Darker Than Death or Night")