Real Dictionary

trajectory
countable noun: The trajectory of a moving object is the path that it follows as it moves.
countable noun: The trajectory of something such as a person's career is the course that it follows over time.

trajectory in American English
the curved path of something hurtling through space, esp. that of a projectile from the time it leaves the muzzle of the gun
noun: the curve described by a projectile, rocket, or the like in its flight

trajectory in British English
noun: the path described by an object moving in air or space under the influence of such forces as thrust, wind resistance, and gravity, esp the curved path of a projectile