The Collaborative International Dictionary of English v.0.48:

Trajectory \Tra*ject"o*ry\, n.; pl. Trajectories. [Cf. F.
   trajectoire.]
   The curve which a body describes in space, as a planet or
   comet in its orbit, or stone thrown upward obliquely in the
   air.
   [1913 Webster] Trajetour
   Trajet