This refers to the law making process in the USA. The passage of a bill from committee to Congress and eventually into law is a complicated process. 
Any member of Congress can introduce a piece of legislation. Once the appropriate committee takes up the bill, they hold hearings to gather opinions from public officials and experts.
When the hearings are complete, a subcommittee "marks up" the bill, making changes and adding amendments before passing it on to the full committee, which can choose to hold additional hearings and make revisions before sending it forward.
In the House of Representatives, most bills go to the Rules committee before reaching the floor. The committee adopts rules that the chamber will use to consider the bill.
A "closed rule," for example, sets strict time limits on debate and forbids the introduction of amendments. These rules can have a significant impact on whether the bill passes.
In the House, bills need only a simple majority of the 435 members to pass. The rules in the Senate, however, are more complicated.
Once a committee refers a bill to the full Senate, any senator can object to it.
If there are no objections, each senator has five minutes to speak on the bill and they can offer amendments.
If, however, there are objections, then each Senator can speak for as long as they like about the bill. Senators can "filibuster" a bill by speaking about it at length.
If the bills passed in the House and the Senate are different, as they usually are, they are then sent to “conference committee” to be reconciled. Then, changes made, the combined version must be passed again by both chambers, except in the rare case where one chamber has agreed to simply adopt the bill passed by the other.
If the bill cannot be reconciled, then it might be referred to another set of lawmakers for conference or if the differences are insurmountable, the bill dies.
But, once a bill is eventually passed by both chambers, it is then sent to the president to be signed into law within 10 days. Unless, of course, the president vetoes the bill, but that is a whole other story.
These days, in practice filibuster just means the threat of blocking the vote. For example, the Republicans threaten to filibuster the Obama’s administration healthcare reform bill.
Sixty votes, rather than the usual 51, are needed to overcome a filibuster.