Meaning of “custodian” - Learner’s Dictionary

custodian

noun [ C ] uk us /kʌsˈtəʊdiən/
VALUABLE THING formal

a person who takes care of something valuable or important:

He's the grandson of Oscar Wilde and custodian of his private papers.
BUILDING US

someone whose job is to look after a building, especially a school

(Definition of “custodian” from the Cambridge Learner’s Dictionary © Cambridge University Press)