A filibuster in the context of the U.S. Senate refers to a procedural tactic used to prolong debate and delay or block a vote on legislation. It allows senators to extend discussion indefinitely unless a supermajority of 60 votes invokes cloture to end it. This strategy can be employed by a minority to assert influence and protect their interests, leading to significant implications for legislative processes. While filibusters can serve as a tool for minority rights, they may also contribute to legislative gridlock, complicating the passage of laws and reforms.