Quorum

A quorum is the minimum number of members who must be present for a deliberative body to conduct official business. Its size and rules are set by governing law or the body’s own rules.

Parliamentary procedure: Rules and practices that govern the conduct of meetings and deliberative assemblies. It supplies procedures for establishing a quorum and responding when attendance falls below it.
Deliberative assembly: A group that meets to discuss and decide matters through debate and voting. A quorum is a condition for this kind of body to conduct official business.
United States Congress: The federal legislature of the United States, composed of the Senate and House of Representatives. The Constitution sets a majority quorum for each chamber to conduct business.
Majority rule: A decision rule under which the option supported by more than half the relevant votes prevails. A quorum concerns who must be present; majority rule concerns how votes decide an outcome.
Roll call: A procedure in which names are called to record attendance or votes. A roll call can establish whether enough members are present to conduct business.
Membership: The status and composition of people belonging to an organization or body. The body’s membership often supplies the base from which its quorum is calculated.
United States Senate: The upper chamber of the United States Congress, with two senators from each state. Its quorum rule shapes how senators establish presence and challenge proceedings.
Supermajority: A voting threshold greater than a simple majority, such as two-thirds or three-fifths. A supermajority sets the votes needed for approval, not the attendance needed to act.
Point of order: A member’s claim that a deliberative body is violating its rules or procedures. A member may raise it when official business proceeds without a required quorum.
Attendance: The presence of people at a meeting or other event. A quorum usually depends on how many members are present at a meeting.

Linked from 11 pages