Child abuse

Child abuse is the abuse, mistreatment or hurt done to children. It often means abuse done by a child's parents or another caregiver. Injuries to the skin like bruises are one of the signs of child abuse.
Talking about these things and helping children who suffer from child abuse is very important, but some people do not believe it could happen in their country, neighbourhood or family. They like to think these crimes are far away and so they cannot see if a child nearby is in danger.
Definition.
The World Health Organization (WHO) defines "child abuse" and "child maltreatment" as "all forms of physical and/or emotional ill-treatment [...] or other exploitation, resulting in actual or potential harm to the child's health, survival, development or dignity in the context of a relationship of responsibility, trust or power." 
In the United States, the Centers for Disease Control and Prevention (CDC) uses the term "child maltreatment" to refer to both acts of abuse and neglect. According to the WHO, the term abuse includes "words or overt actions that cause harm, potential harm, or threat of harm to a child"; neglect means "the failure to provide for a child's basic physical, emotional, or educational needs or to protect a child from harm or potential harm". 
The United States federal Child Abuse Prevention and Treatment Act defines "child abuse and neglect" as, at minimum, "any recent act or failure to act on the part of a parent or caretaker which results in death, serious physical or emotional harm, sexual abuse or exploitation" or "an act or failure to act which presents an imminent risk of serious harm".