WordNet sense 1 (the state of being connected):

connection, connectedness

WordNet sense 2 (a connecting shape):

connexion

WordNet sense 3 (the means of connection between things linked in series):

nexus

WordNet sense 4 (a channel for communication between groups):

contact, liaison, contact, inter-group communication

WordNet sense 5 (an interconnecting circuit between two or more locations for the purpose of transmitting and receiving data):

data link

WordNet sense 6 (a fastener that serves to join or connect):

linkup, tie, tie-in

WordNet sense 7 (a two-way radio communication system (usually microwave); part of a more extensive telecommunication network):

radio link

WordNet sense 8 (be or become joined or united or linked):

connect, join, unite

WordNet sense 9 (link with or as with a yoke):

yoke

WordNet sense 10 (make a logical or causal connection):

associate, relate, colligate, associate, tie in