Conversation so far:
What was Tom Coburn's senate career?
After three years out of politics, Coburn announced his candidacy for the Senate seat being vacated by four-term incumbent Republican Don Nickles.
Did Tom Coburn win the position of Oklahoma senator?
Yes, Tom Coburn won the position of senator against Brad Carson by a margin of fifty-three percent.
What did Tom Coburn do after he won the position of Oklahoma senator?
Coburn used the Senate hold privilege to prevent several bills from coming to the Senate floor.

Question: What does this mean?
Self-contained rewrite: What does Senate hold mean?