Other forms: linkages
Linkage means "connection"––the act of linking or the fact of being linked––specifically the kind of connection where one thing follows the other, as if in a chain.
A relatively new word (from the mid-19th century), linkage has a scientific or at least a technical ring to it, and it's often used in scientific or diplomatic contexts. In peace negotiations, there is usually a linkage between agreement to cease fire and the meeting of other demands. The connection by which genes travel together from one generation to the next is called linkage.