quorum

thumb|right|Vote cast against Themistocles. A quorum of 6,000 was required for [[ostracism under the Athenian democracy, according to Plutarch; a similar quorum was necessary in the following century for grants of citizenship.]] A quorum is the minimum number of members of a group necessary to constitute the group at a meeting. In a deliberative assembly (a body that uses parliamentary procedure, such as a legislature), a quorum is necessary to conduct the business of that group. In contrast, a plenum is a meeting of the full (or rarely nearly full) body. A body, or a meeting or vote of it, is quorate if a quorum is present (or casts valid votes).

The term quorum is from a Middle English wording of the commission formerly issued to justices of the peace, derived from Latin quorum, "of whom", genitive plural of qui, "who". As a result, quora as plural of quorum is not a grammatically well-formed Latin-language construction. In modern times, a quorum might be defined as the minimum number of voters needed for a valid election. Quorums are often part of parliamentary procedure.