Leader of the Opposition in the Senate (Canada)

In Canada, the leader of the Opposition in the Senate (French: Chef de l'opposition au Sénat) is the leader of the largest party in the Senate not in government. Even though the position's name is very similar to the leader of the Opposition in the House of Commons (the Opposition House leader), the leader of the Opposition in the Senate's role is more analogous to the leader of the Official Opposition because its holder is the leader of the party's Senate caucus.

Source: Wikipedia — Leader of the Opposition in the Senate (Canada) (CC BY-SA 4.0)