What is a projectile?
Projectile
any object  thrown into space (empty or not) by the exertion of a force
A projectile is any object  thrown into space (empty or not) by the exertion of a force.[1] Although any object in motion through space (for example a thrown baseball) may be called a projectile, the term more commonly refers to a ranged weapon.[2][3] Mathematical equations of motion are used to analyze projectile trajectory.