Physical development is the way in which the body learns skills, becoming more complex in performance: Early Childhood Care & Education Assignment, UOL, Ireland

The Physical Child

Physical development is the way in which the body learns skills, becoming more
complex in performance. Physical development is the most visible of all the
abilities shown in childhood and includes the less observable development of the
senses, hearing, vision, touch, taste, and smell.

• Physical means anything to do with the body and can be used in a wide
  range of contexts, from how people look physically to how they move
  physically.
• Development means a change in performance and is usually associated
  with progression, becoming more complicated or skillful. It can also be
  defined as an increase in complexity.

There is a recognized pattern of physical development, which is expected that
children will follow. These are known as the developmental norms. Norm should
not be confused with normal, a word which is not encouraged when describing
physical development because there is such a wide range of normal development.

It is dangerous to assume that children are abnormal if they do not all progress
in a similar manner. Variations will always exist, as each child is an individual
developing in their own unique way. Knowledge of patterns of development helps
us to look at the child as a whole, and to measure their progress as an individual.