Geodesic

Bodies like the earth are not made to move on curved orbits by a force called gravity; instead they follow the nearest thing to a straight path in a curved space, which is called a geodesic. 

A geodesic is the shortest (or longest) path between two nearby points. Eg: the earth is a 2D curved space. A geodesic on the earth is called a great circle and is the shortest route between two points. 

In general relativity, bodies always follow straight lines in four-dimensional space time, buy they nevertheless appear to us to move along curved paths in our three dimensional space. 

The mass of the sun curves space-time in such a way that although the earth follows a straight path in 4D space-time, it appears to us to move along a circular orbit in the 3D space.