Geodesic
Geodesic is a term comes from the word geodesy that means the measure the size and shape of earth. Geodesic is a shortest route between two point on the surface of earth. According to geometry, Geodesic is a generalized notion of a straight line to curved spaces.
In general theory of relativity, geodesic is more important. Here curvature geodesic is more considerable than straight line geodesic. The motion of free falling test particle is described in general theory of relativity by geodesic.