A young pig. Obsolete.

In legal and official contexts: an adolescent, a youth. Usually in plural.

A person in the age of adolescence; a youth. Also: an animal at an analogous stage of development.

In expressing the age of a person (rarely also of a thing): any of the years whose numbers end in -teen… A person who is in his or her teens.

A person in his or her teens; a teenager.

A young person who has (recently) been through puberty.

A person who is in his or her teens; (more generally) an adolescent. Also in extended use.

= teeny, n.2

A young teenager or a pre-teenager, esp. one who is a fan of pop music; a teeny-bopper.

A child who is nearly, or has only just become, a teenager. Cf. tween, n.2

the age at which a young person is likely to wear jeans; so jean-aged adj.; jean-ager.

slang (originally and chiefly British). Short for skinhead, n. 1b.