The transitional period between childhood and adulthood is called Adolescence.

Adolescence is a crucial phase in an individual's life that marks the transition from childhood to adulthood. It is a period of significant physical, psychological, and social changes as young people navigate their way towards independence and self-identity. This phase usually begins with the onset of puberty and continues until the individual reaches adulthood, typically around the age of 18 or 19.

Key Points:
- Definition: Adolescence is the period between childhood and adulthood.
- Transition: It marks a time of significant physical, psychological, and social changes.
- Onset: Adolescence usually begins with the onset of puberty.
- Duration: It continues until the individual reaches adulthood, around the age of 18 or 19.

Physical Changes:
- Puberty: Adolescence is often characterized by the onset of puberty, when the body undergoes significant physical changes such as the development of secondary sexual characteristics like facial hair in males and breast development in females.
- Growth Spurts: During this period, young people experience rapid growth spurts, both in height and weight, as their bodies prepare for adulthood.
- Hormonal Changes: Adolescence is also marked by hormonal changes that contribute to sexual and reproductive maturity.

Psychological Changes:
- Identity Formation: Adolescents often grapple with questions of self-identity, trying to understand who they are and where they fit in the world.
- Emotional Rollercoaster: Hormonal changes can lead to mood swings and emotional turbulence, as young people navigate the complexities of their changing emotions.
- Abstract Thinking: Cognitive abilities continue to develop during adolescence, allowing individuals to engage in more complex and abstract thinking.

Social Changes:
- Peer Relationships: Adolescents often place a higher value on their peer relationships, seeking acceptance and validation from their friends. These relationships become more influential during this period.
- Independence: As adolescents strive for autonomy, they may challenge authority figures and seek more independence in decision-making.
- Exploration and Experimentation: Adolescence is a time of exploration and experimentation, as individuals try out different identities, values, and behaviors.

Conclusion:
Adolescence is a critical and transformative period in an individual's life. It encompasses physical, psychological, and social changes that shape one's transition from childhood to adulthood. Understanding and supporting young people during this phase is essential for their healthy development and successful navigation into adulthood.