3. institution a place for the care or confinement of people, as mental patients.
4. institution a well-established and structured pattern of behavior or of relationships that is accepted as a fundamentalpart of a culture: the institution of marriage.
5. institution any established law, custom, etc.
6. institution any familiar, long-established person, thing, or practice; fixture.
3. (noun)institution a custom that for a long time has been an important feature of some group or society "the institution of marriage"; "the institution of slavery"; "he had become an institution in the theater"
4. (noun)initiation, founding, foundation, institution, origination, creation, innovation, introduction, instauration the act of starting something for the first time; introducing something new "she looked forward to her initiation as an adult"; "the foundation of a new scientific society"
5. (noun)mental hospital, psychiatric hospital, mental institution, institution, mental home, insane asylum, asylum a hospital for mentally incompetent or unbalanced person
4. (noun)institution that which instituted or established
5. (noun)institution established order, method, or custom; enactment; ordinance; permanentform of law or polity
6. (noun)institution an established or organized society or corporation; an establishment, especially of a public character, or affecting a community; a foundation; as, a literary institution; a charitable institution; also, a building or the buildings occupied or used by such organization; as, the Smithsonian Institution
Definitions of institution 
