A grouping of two or more music staffs is called a what?

More than one staff can be grouped with a bracket or a brace to create a system. The bracket typically groups independent parts to form a system. In the example below, the voice parts (soprano, alto, tenor, and bass) are connected with the bracket to create visual grouping of the voice parts.

I like to play guitar, hangout with friends and family, play softball, bake, read, swim, ride the quad, hike, camp, run track, and sing. I'm currently not in any clubs. Some of my favorite tv shows are Once upon a time, I love Lucy, and Liv and Maddie. My favorite book series is The Land of Stories.  

Explanation: