Medicare is a social insurance program that serves more than 44 million enrollees (as of 2008). The program costs about $432 billion, or 3.2% of GDP, in 2007.
The definition of an institution is an established custom or practice, or a group of people that was formed for a specific reason or a building that houses the group of people. 1  Marriage is an example of a cultural institution. 2  A town council is an example of an institution of government.
The term institution commonly applies to both informal institutions such as customs, or behavior patterns important to a society, and to particular formal institutions created by entities such as the government and public services.