WordNet sense 1 (the state of being connected):

link, connectedness

WordNet sense 2 (a connecting shape):

connexion

WordNet sense 3 (the process of bringing ideas or events together in memory or imagination):

association

WordNet sense 4 (an instrumentality that connects):

connecter, connective, connector

WordNet sense 5 (the act of bringing two things into contact (especially for communication)):

joining