partner-n; 4 Senses

Sense Number 1: a spouse or significant other

Commentary: PARTNER[+role][+associate][+social][+domestic]

John's domestic partner does not receive health benefits on his insurance plan.
The newlyweds hoped to be partners for life.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: a collaborator pursuing a shared goal

Commentary: PARTNER[+role][+collaborator]

Bob escorted his dance partner to the center of the dance floor.
The two brothers were partners in crime.
The young heavyweight needs a new sparring partner to train with.
The two firms have been each other's sparring partner for years. (metaphoric)

WordNet 3.0 Sense Numbers: 2

Sense Number 3: an principal member of a business association

Commentary: PARTNER[+role][+associate][+business][+principal]

Bob made partner at that law firm in just four years.
The venture capitalist confided that he is a silent partner for two biotech startups.
The two firms may arrange a partner relation for the proposed spin-off.
The partners are having a meeting tomorrow to decide whether to bring Mary on board.

WordNet 3.0 Sense Numbers: 3

Sense Number 4: strong timbers on a ship's deck

Commentary: PARTNER[+artifact][+timber][+strong][+ship]
NOTE: usually in the plural

The boat inspector carefully looked over the partners of the main deck.

WordNet 0.0 Sense Numbers: 4