an organization, establishment, foundation, society, or the like, devoted to the promotion of a particular cause or program, esp. one of a public, educational, or charitable character

This college is the best institution of its kind.

the building devoted to such work.

a public or private place for the care or confinement of inmates, esp. mental patients or other disabled or handicapped persons.

Sociology . a well-established and structured pattern of behavior or of relationships that is accepted as a fundamental part of a culture, as marriage

the institution of the family.

any established law, custom, etc.

any familiar, long-established person, thing, or practice; fixture.

the act of instituting or setting up; establishment

the institution of laws.

Ecclesiastical .

the origination of the Eucharist, and enactment of its observance, by Christ.

the investment of a member of the clergy with a spiritual charge.

noun

academy , association , asylum , business , clinic , college , company , conservatory , establishment , fixture , foundation , guild , hospital , institute , institution , orphanage , school , seminar , seminary , society , system , university , constitution , creation , organization , origination , start-up