running mate noun
plural ∼ mates [count] chiefly US : the person who runs with someone in an election (such as an election to choose a new president) and who is given the less important position (such as vice president) if they are elected
▪ When John F. Kennedy ran for president, his running mate was Lyndon Johnson.
▪ When John F. Kennedy ran for president, his running mate was Lyndon Johnson.
