1. established organizations or foundations, especially of a public or educational nature
2. established laws, practices, or customs in a society or community
3. large important organizations that provide a particular service

Examples

• Harvard and Yale are prestigious educational institutions.
• Financial institutions like banks help manage money.
• Democratic institutions protect citizens’ rights.
• The museum is one of the city’s cultural institutions.
• Marriage and family are important social institutions.
• Medical institutions provide healthcare services to the community.
• Religious institutions play a significant role in many societies.