Noun
appropriate adult (plural appropriate adults)
(UK, law) An adult, such as a parent, guardian, or social worker, whose role is to safeguard the interests of young people detained by the police, and who must be present at such interviews.
“Childline staff and volunteers are dedicated to providing our Helpline and our Appropriate Adult service every day of the year, no matter what the circumstances” explained Annie Green, Chairperson of Childline Gibraltar. Source: Internet