institution-n; 4 Senses

Sense Number 1: An established organization, e.g., corporation, government

Commentary: INSTITUTION[+entity][+social][+group][+organization][+established]

Examples:
The World Charity Foundation is a non-profit institution.
John's religion is an institution devoted to belief in a divine power.
Yale University is an educational institution of some regard.
She received a diploma from an accredited institution.

Mappings:
WordNet 3.0 Sense Numbers: 1

Sense Number 2: A building or group of buildings

Commentary: INSTITUTION[+entity][+structure][+building] Refers specifically to a physical establishment

Examples:
The Institution for Research in the Cognitive Sciences is located at 3401 Walnut Street.
He has spent much of his life in institutions. (elliptical for 'mental institution')
That building used to be an institution for the severally handicapped.
The island housed a penal institution, from which escape was believed impossible.

Mappings:
WordNet 3.0 Sense Numbers: 1

Sense Number 3: A custom

Commentary: INSTITUTION[+state][+social][+long_standing][+custom] A custom, usually very old, that is an important part of some group or society.

Examples:
For many years, slavery was America's "peculiar institution".
The institution of marriage is constantly being threatened.
After running for ten years, "Cats" had become a Broadway institution.
Private property and public elections are institutions of democratic societies.

Mappings:
WordNet 3.0 Sense Numbers: 1

Sense Number 4: initiation, founding, introduction of something

Commentary: INSTITUTION[+event][+action][+initiate][+undertaking] Something begun, organized, or introduced.

Examples:
The institution of a new scientific society was a cause for celebration.
Senator John pushed for the re-institution of capital punishment.
There was a delay in the institution of the legal proceedings.

Mappings:
WordNet 3.0 Sense Numbers: 1