Physical growth is an increase in body size and weight.
Development is a change in body function or skill.
Growth and development follow orderly patterns - from top down or from head to foot. A child will gain control of his head before he sits, and he will sit before he walks. Development moves from the centre of the body to the outside. A child will roll over before he can control objects with his hands. A baby first reaches clumsily for a toy, then learns to scoop it up with his whole hand.