noun pl. trajectories -·ries

1. the curved path of something hurtling through space, esp. that of a projectile from the time it leaves the muzzle of the gun
2. Math.
   1. a curve or surface that passes through all the curves of a given family at the same angle
   2. a curve or surface that fits a particular law such as passing through a given set of points

Etymology: ML trajectorius < L trajectus: see traject