intercommunˈion or intercommunicaˈtion noun

1. Mutual communion or relation, esp between churches
2. The permitting of members of one denomination to receive Holy Communion in the churches of another denomination

intercommunˈity noun

The state of being or having in common

letters of intercommuning

An ancient writ issued by the Scottish Privy Council warning people not to harbour or have any dealings with those named, on pain of being held accessory