linkage
noun /ˈlɪŋkɪdʒ/
  /ˈlɪŋkɪdʒ/
- [uncountable, countable] linkage (between A and B) the act of linking things; a link or system of links synonym connection
- This chapter explores the linkage between economic development and the environment.
 
 - [countable] a device that links two or more things