The period of transition between childhood and adulthood is called

Adolescence

Explanation:

Growing from being a child to being an adult involves a phase called Adolescence. It is a stage in human life where one has stopped being a child (due to behavioural and physical changes) but not yet in a position to be called an adult. According to WHO, a person between ages 10-19 can be considered an adolescent.

Adolescence period is characterized by certain physical, behavioural and emotional modifications in the human body. Conspicuous physical changes include development of features pertaining to the sex of each individual e.g females begin to develop breasts and widening of their hips while males develop a broadened chest and beards/facial hair.

At this stage, adolescents also undergo rapid growth portrayed by their height and weight. They also undergo changes in their behavior as they become more cognizant of others impression of them.