Youth is defined by Webster's New World Dictionary as, "The time of life when one is young; especially: a: the period between childhood and maturity b: the early period of existence, growth, or development."
Around the world the terms "youth", "adolescent", "teenager", and "young person" are interchanged, often meaning the same thing, occasionally differentiated. Youth generally refers to a time of life that is neither childhood nor adulthood, but rather, somewhere in-between. Youth also identifies a particular mindset of attitude, as in "He is very youthful". The term youth is also related to being young.