Definition of protective custody:
(n) :
(law enforcement) Lawful confinement of a person or close supervision of his or her movements, on a voluntary or involuntary basis, by authorities in order to safeguard that person from attack or other dangers.
(n) :
(law enforcement) The custody that CPS sometimes takes of children when those children are being abused or neglected and no other corrective action is successful or feasible.