noun (n)

• an organization founded and united for a specific purpose(noun.group)

  Synonym:
  establishment
  

  source: wordnet30
• an establishment consisting of a building or complex of buildings where an organization for the promotion of some cause is situated(noun.artifact)

  source: wordnet30
• a custom that for a long time has been an important feature of some group or society(noun.cognition)

  Example:
  The institution of marriage.
  The institution of slavery.
  He had become an institution in the theater.
  

  source: wordnet30
• the act of starting something for the first time; introducing something new(noun.act)

  Synonym:
  creation, foundation, founding, initiation, innovation, instauration, introduction, origination
  

  source: wordnet30
• a hospital for mentally incompetent or unbalanced person(noun.artifact)

  Synonym:
  asylum, insane asylum, mental home, mental hospital, mental institution, psychiatric hospital
  

  source: wordnet30
• The act or process of instituting; as: (a) Establishment; foundation; enactment; as, the institution of a school.(noun)

  source: webster1913