In topic Kinematics, previously we almost talk about one dimensional motion. Now from this session, let's start to talk about two dimensional motion - called Projectile motion. In such type of motion, gravity is the only factor acting on our objects (neglecting the air resistance, acceleration due to gravity is downward and constant).
Any object thrown into atmosphere so that it falls under the effect of gravity alone is called Projectile motion.
Projectile motion: is a form of motion in which an object (particle) i.e. called a projectile is thrown near the Earth's surface, and it moves along a curved path under the action of gravity only. (wikipedia)