Inappropriate adolescent or adult sexual behavior with a child. It includes fondling a child's genitals, making the child fondle the adult's genitals, intercourse, incest, rape, sodomy, exhibitionism, sexual exploitation, or exposure to pornography. To be considered child abuse, these acts have to be committed by a person responsible for the care of a child (for example a baby-sitter, a parent, or a daycare provider) or related to the child. If a stranger commits these acts, it would be considered sexual assault and handled solely be the police and criminal courts.
Source: Children Welfare Information Gateway