From AionSource.com Wiki
The word Simabandha in Sanskrit means binding or joining, a close connection or union or association, conjunction, inherence, connection with or relation to. It connotes personal connections like a relationship, fellowship, friendship and even intimacy. The word ‘sambandhi’ (or as used ‘samdhi’) refers to a kinsman, a relationship brought about by a marriage or family by birth.
Simbandha, when relating to Aion's lore, perhaps denotes a land between Atreia's two halves, or perhaps the middle section of the Tower of Eternity.