An object's orbit is the path it takes through the simulation under the influence of gravity. In Universe Sandbox, the term "orbit" usually refers to closed or repeating orbits (with an eccentricity less than 1), and the path taken by an object with a parabolic or hyperbolic eccentricity (greater than or equal to 1) is usually called a "trajectory". The object exerting the gravitational force on the orbiting object is called its Orbital Parent.
An orbit can be mathematically described with five properties: the semi-major axis, eccentricity, inclination, longitude of the ascending node, and argument pericenter. Along with the true anomaly or mean anomaly, which describe an object's position along its orbit, these six properties are collectively called the object's orbital elements.