youth, adolescent, teenager, and young person are interchanged, often meaning the same thing, occassionaly differentiated. Youth generally refers to a time of life that is neither childhood nor adulthood, but rather, somewhere in-between. A teenager or teen is a person whose age is a number ending in teen in the English language: that is to say, someone from the age of 13 to the age of 19.

Many argue that in Western culture, a distinct youth culture has developed. This culture is often distinctly different from the mainstream culture, sometimes in rebellion against it, and thus is often referred to as a subculture or counterculture. This rebellion is also referred to as youth voice, and is used in positively ways, including youth leadership and youth participation activities.