1. the way in which two or more people or things are connected or related to each other
2. a romantic or sexual association between two people
3. the state of being related by blood or marriage

Examples

• The relationship between diet and health is well documented.
• She has a close relationship with her sister.
• They’ve been in a relationship for three years.
• The company values its relationship with customers.
• There’s no relationship between those two events.
• He’s looking for a serious relationship.
• The relationship between supply and demand affects prices.