Uncle is a term used to refer to:
1. The brother of one's parent
2. The husband of one's aunt
3. A term of respect for an older man (informal)
4. In slang, can mean "a pawnbroker" (British English)
5. In African American Vernacular English (AAVE), can be used as a general term of respect for a male elder
6. In finance, "Uncle Sam" refers to the U.S. government