1. to join together; to unite or connect with another person or thing
Usage: archaic or formal; often used in legal or ceremonial contexts

Examples

• The two families cojoined their estates through marriage.
• The documents were cojoined to form a single legal agreement.
• They cojoined their efforts to complete the project on time.
• The rivers cojoin at the valley below.
• The partners cojoined their resources to start the business.