Survivors of child sexual abuse
A survivor of child sexual abuse is a person who has not died while being (supposedly) sexually abused, that is, while engaging in sexual activity with an older person or an adult (usually a male).
As it is extremely rare that sexual abuse ever causes the death of a child, the use of the term "survivor" is questionable.
Origin of the term
There were no "survivors of child abuse" until certain feminists organized groups of women in the 1980s who had had experiences, as minors, of sexually activity with adults. To sensationalize the women's experiences, these woman began to call themselves "survivors".