To have a referendum means to give people the opportunity to vote on an important issue or question that affects a whole country or community. It is a way of making decisions by allowing everyone to have a say through voting. Full definition
By custom (and its text), parliament can only change it by consulting with the provinces and having a referendum on the subject with certain strict criteria to pass the amendment. (politics.stackexchange.com)
We want to have this referendum in order to prevent instability. (foreignpolicy.com)
We do have a referendum process; it is required for bond issues and to amend the state constitution. (nystateofpolitics.com)