a juvenile between the onset of puberty and maturity
"The teenager struggled to balance her growing independence with the responsibilities expected of an adult."
A person between 13 and 19 years of age; an adolescent.
"The school principal warned all teenagers that breaking curfew would result in suspension."
In plain English: A teenager is someone who has passed through childhood but is not yet an adult, usually between the ages of thirteen and nineteen.
"The teenager stayed up late playing video games with his friends."
Usage: Use this term to refer specifically to individuals aged thirteen through nineteen, distinguishing them from younger children or adults. It is a neutral descriptor for adolescents that avoids the negative connotations sometimes associated with words like "youth" in casual contexts.
The word teenager combines the adjective teenage with the suffix -er to denote a person of that age group. It was first used in the early 20th century to specifically refer to adolescents between the ages of thirteen and nineteen.