a legislative act is referred for final approval to a popular vote by the electorate
"The parliament decided to submit the controversial tax bill to a referendum so that the people could give it final approval."
A direct popular vote on a proposed law or constitutional amendment. The adposition on is usually used before the related subject of the vote.
"The state will hold a referendum on whether to change its constitution regarding voting rights."
In plain English: A referendum is when people vote directly on an important question to decide if something should happen.
"The country held a referendum to decide whether to change its constitution."
Usage: Use on to introduce the specific proposal being voted upon, as in a referendum on tax reform. This word applies only when citizens directly decide an issue rather than electing representatives to make that decision for them.
The word comes from the Latin referendum, meaning "that which ought to be announced." It entered English with this original sense of a matter being reported or presented for decision.