partner /ˈpɑːtnər/ noun [C]
RELATIONSHIP › someone that you are married to or having a sexual relationship with: sexual partners Are partners invited to the office dinner?
SPORTS/DANCING › someone that you are dancing or playing a sport or game with
BUSINESS › someone who owns a business with another person: a junior/senior partner He's a partner in a law firm.
COUNTRY › a country that has an agreement with another country: a trading partner Britain and its European partners