A child (plural form is children) is a person who is not an adult yet, or who has not reached puberty, which usually happens in adolescence. Sometimes, tweenagers (pubescents) and teenagers (postpubescents) are also called children. A baby that is not yet born is often called a child, too. A person can be called his or her parent's child, no matter how old he or she is. Some synonyms for the word 'child' are "kid", "toddler", "bairn", "youngster", "boy" or "girl, lad" or" lass", and" youth. "