Adolescence (lat adolescere, (to) grow) is a transitional stage of physical and mental human development that occurs between childhood and adulthood. This transition involves biological (i.e. pubertal), social, and psychological changes, though the biological or physiological ones are the easiest to measure objectively. Historically, puberty has been heavily associated with teenagers and the onset of adolescent development.[1][2] In recent years, however, the start of puberty has had somewhat of an increase in preadolescence (particularly females), as well as an extension beyond the teenage years (typically males). This has made adolescence less simple to discern.[3][4][5]   «   Summary from Wikipedia