English Reference
noun

custodian

n.
US /kəˈstoʊdiən/ UK /kʌstˈəʊdiən/ cus·to·di·an UK spelling custodian's, custodian's

  1. 01 C1 Advanced Formal

    someone who is responsible for protecting or looking after something important, like a tradition, a building, or a child.

    a person entrusted with the custody or care of something or someone; a protector of assets, values, or legal interests.

    Simple

    The museum acts as the custodian of the nation's most important historical documents.

    In context

    As the sole custodian of the family estate, she felt a heavy responsibility to preserve the land for future generations.

    Usage

    Often followed by the preposition 'of'.

  2. 02 B2 Upper Intermediate American English

    a person whose job is to clean and take care of a large building, like a school.

    a person employed to clean and maintain a building, such as a school or office complex.

    Simple

    The school custodian made sure all the classrooms were clean before the students arrived.

    In context

    The head custodian reported that the heating system required urgent repairs before the winter term began.

    Teacher's tip

    In British English, 'caretaker' is the standard term for this role; 'custodian' is almost exclusively used for the 'guardian' sense.

The Bank is one of the largest custodians of gold in the world.

BBC News· 5 Sept 2026

Decision makers must strike a delicate balance as they redefine their roles as custodians of culture in an era when technology empowers them to do so much.

Ars Technica· 25 Jul 2026

From a shortening of Latin custōdiānātus, from Latin custōdia (“a keeping, watch, guard, prison”), from custōs (“a keeper, watchman, guard”). By surface analysis, custody + -ian.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin custōdia
Level C1 · Advanced
Frequency Occasional
Updated