noun

• The act of combining that occurs where two rivers meet.
• The place where two rivers, streams, or other continuously flowing bodies of water meet and become one, especially where a tributary joins a river.
• The stream or body formed by the junction of two or more streams; a combined flood.
• A convergence or combination of forces, people, or things.
• (biology) The proportion of cells, in a culture medium, that adhere to each other.
• (computer science, in rewriting systems) A property describing which terms can be rewritten with other, equivalent terms.