A person who has no siblings. / A person raised as the sole child in a household.

A child who is raised without human contact as a result of being abandoned, allegedly often raised by wild animals.

(psychology) The childlike aspect of a person's psyche — typically, the personality and the memories of one's childhood — especially in context of coexisting with, and being suppressed by, an adultlike aspect of the person.

(transitive) To impregnate.

(idiomatic) Something particularly simple or easy. / Used other than figuratively or idiomatically: the play of a child.

(with "years" or "age") Pertaining to the time between puberty and menopause when a woman is able to bear children.

(Christianity) the child Jesus

(euphemistic) A child who is particularly difficult to raise or educate, especially due to a lack of self-control and disruptive and antisocial behavior.

(chiefly Canada, US, idiomatic) One who is a prototypical or quintessential example of something.

A child in a developing country whose parents have found employment abroad. The stereotype is one of relative financial well-being, but emotional detachment from the parents.