Grief is a multi-faceted response to loss, particularly to the loss of someone or something to which a bond was formed. Although conventionally focused on the emotional response to loss, it also has physical, cognitive, behavioral, social, and philosophical dimensions. Common to human experience is the death of a loved one, whether it be a friend, family, or other companion. While the terms are often used interchangeably, bereavement often refers to the state of loss, and grief to the reaction to loss.