TwinLink

 Given TwinWikis T1,T2 with TwinPages P1,P2 =>

 L1 on P1 is TwinLink to P2 :<=> Clicking L1 navigates to P2

Discussion:

As TwinWikis T1,T2 with TwinPages P1,P2 are arbitrary, we need not explicitly write:

  ** L2 on P2 is TwinLink to P1 :<=> Clicking L2 navigates to P1

Preferably the appearance of a TwinLink, coming in form of an icon, is called a TwinIcon.