1. (countable and uncountable, nautical) The post of mate on a ship; a posting as mate.
2. (countable, whaling, obsolete) A type of contract between ships to cooperate and share the proceeds of an expedition.
3. (uncountable) Fellowship; companionship.
4. (uncountable, Australia, New Zealand) Friendship, particularly between men, such as develops in shared adversity; solidarity.
5. (countable, zoology, psychology, anthropology) A relationship based on mating.