Partnership is a mode of relationship that goes beyond the standard / natural mode usually observed in a given environment.
1) ie in business : beyond sell / buy
2) ie at the personal level : beyond love / hatred, family / friendship
3) ie in the wilderness : beyond symbiosis / parasitism / predation
Binding or not, a partnership is decided by all parties and requires their involvement and agreement.
=> Partnership truly requires intelligence, an understanding of one's environment beyond the natural reach. In a successful partnership, both parties fully understand each other's environment, which generaly includes a new point of view on their selves.
(answer to the question "Partnership - what is it ?")