A referendum is a type of POLL or VOTE in which citizens are asked to directly decide on a particular issue. It is usually used to refer to a general VOTE by the public on a single political question that has been referred to them for a direct decision. A POLL is a survey of public opinion, usually conducted by asking a sample of people a series of questions. A VOTE is a formal expression of opinion or will in response to a proposed decision. A PLEBISCITE is a direct VOTE by the entire electorate on a single political question that has been referred to them for a direct decision.