DS stands for defensive specialist - a player who specializes in playing in the backrow, or passing
deep safety - in a prevent defense this position usually replaces one of the linebackers...
It stands for the Defensive Specialist who is often times the middle back. They almost always play back row.
Defensive Specialist Sometimes called a libero
Ds stands for "double screen'' as in the two ds screens.
There are usually 2 referees in a volleyball game. One is on the stand and one is on the floor.
Dual Screen. Simple.
mb stands for middle blocker.