›formala person with responsibility for protecting or taking care of something or keeping something in good condition: the custodian of a museum/castleProtection and protectorsEnvironmental issues›formalsomeone who tries to protect particular ideas or principles: She sees herself as a custodian of the public's morals.Supporters, members and defendersBelievers and non-believers›US forcaretakerProtection and protectorsEnvironmental issues