The youngest person (or animal, etc.) in a particular context; esp. (sometimes with possessive) the youngest child or sibling.

With possessive adjective: a person's inferior in age; = junior, n. 1b. Now usually in plural. Cf. elder, n.3 2a, older, n. 2b.

Usually with the: (with singular sense) the person who is the least old of two or more people; (with plural sense) those who are younger, considered…

(the adjective used absol.) A person who is younger than another, or of more recent entrance or lower standing in a class, profession, etc.: see…

A lively or energetic young person; spec. a confident, high-spirited young man; (esp. in the 18th cent.) a rake, a dandy; an unruly young…

gen. A person younger or more junior than another or others; a junior. Obsolete.

gen. A junior; an inferior, an underling; a novice. Obsolete.

slang. A child, esp. a young child. (Originally low slang, but by the 19th cent. frequent in familiar speech.)

In certain British boys' public schools (used as postmodifier): designating the youngest or (occasionally) the newest of several pupils with the…

In extended use. The youngest person in a family, group of people, etc. Also: the most junior member of a team or other group. Frequently with of.

In British public schools: the younger brother of a pupil at the school. Obsolete. rare.