partnership-n; 2 Senses

Sense Number 1: members of a business or firm, contractually bound together

Commentary: PARTNERSHIP[+organization][+business] [+relation][+legal][+contractual]
NOTE: implies a legal, binding contract among members

He joined that legal partnership in 1995.
Several successful entrepreneurs formed a partnership to provide seed money to promising biotech start-ups.
That California winery now has partnerships with two Italian and two French winemakers.

WordNet 3.0 Sense Numbers: 1, 3

Sense Number 2: people or organizations in cooperative relationships

Commentary: PARTNERSHIP[+relation][-legal][+cooperative] [+activity][+collaboration]
NOTE: generally implies an informal, non-binding, cooperative relationship

These volunteer groups work in partnership with local law enforcement agencies.
The director of that film developed a close partnership with the screen writer during the shoot.
There is no longer the partnership between parents and teachers that once existed.

WordNet 3.0 Sense Numbers: 2