custodian

noun

1. A person entrusted with the custody or care of something or someone; a caretaker or keeper.

   “After their parents' death, their aunt became the children's custodian.”

   “The building's custodian could fix nearly anything. The place always looked great!”

   “The middle class is the. demitone of human society, custodian of the balance, and no fair social order could exist without the cooperation of this class.”

   “Dr. Weber and her colleagues are the latest custodians of the Beal seed viability experiment: a multicentury attempt to figure out how long seeds can lie dormant in the soil without losing their ability to germinate.”

2. An administrator.
3. A gaolkeeper.
4. A protector or guard.
5. (Canada, US)A janitor; a cleaner.