In a speech to the electorate at Bristol in 1774, Edmund Burke described the British Parliament as a "deliberative assembly," and the expression became the basic term for a body of persons meeting to discuss and determine common action.
A member of a deliberative assembly has the right to attend meetings, make motions, speak in debate, and vote. Organizations may have different classes of members (such as regular members, active members, associate members, and honorary members), but the rights of each class of membership must be defined (such as whether a "member" in a class has the right to vote). There may also be ex-officio members, or persons who are members by virtue of some other office or position they hold. Ex-officio members have the same rights as other members.
Robert's Rules of Order Newly Revised identifies several types of deliberative assemblies.
A mass meeting, which is an unorganized group meeting open to all individuals in a sector of the population who are interested in deliberating about a subject proposed by the meeting's sponsors. Examples include meetings to discuss common political concerns or community interests.
A local assembly of an organized society, which is a membership meeting of a local chapter or branch of a membership organization. Examples include local chapter meetings of organizations like the Sierra Club.
A convention, which is a meeting of delegates who represent constituent units of a population. Conventions are not permanently established bodies, and delegates are normally elected for only one term. A convention may be held by an organized society, where each local assembly is represented by a delegate.
A legislative body, which is a legally established public lawmaking body. It consists of representatives chosen by the electorate. Examples include national legislatures such as parliaments, and local government councils such as state legislatures, regional assemblies and city councils.
A board, which is an administrative, managerial, or quasi-judicial body. A board derives its power from an outside authority that defines the scope of its operations. Examples include an organized society's or company's board of directors and government agency boards like a board of education.
A committee is a body of one or more persons subordinate to a deliberative assembly. A committee is not itself considered to be a form of assembly.