Plural of “referendum”

The plural of referendum is referendums (some dictionaries also accept referenda).

Why

"Referendum" is unusual among Latin borrowings because it isn't a regular noun in Latin at all — it's a gerundive of "referre," "to bring back" or "to refer," meaning literally "a thing that must be referred" (to the people, for a vote). Because it started life as a verb form rather than a true noun, classical Latin never actually had a plural "referenda" for it in the sense modern English uses; the plural was constructed by later English and European usage on the model of other Latin -um nouns, not inherited directly from ancient Latin grammar.

That grammatical quirk is exactly why "referendums" has become the preferred plural in most careful modern style guides: since "referenda" isn't a genuine inherited Latin plural but a modern approximation of one, there's less historical weight behind it than there is for words like "data" or "strata" that really were true Latin plurals in everyday ancient use. Political scientists and journalists increasingly favor "referendums" partly for this reason, and partly because it avoids any confusion with the unrelated word "agenda" (itself a former gerundive plural that fully became an English singular noun).

Usage note

"Referendums" is now the more common and more recommended plural in journalism, political science, and general usage; "referenda" still appears, especially in British and academic writing, and isn't wrong, but it's worth knowing that its Latin pedigree is shakier than it looks.

Not every public vote is technically a referendum: a referendum specifically asks voters to approve or reject a particular law or policy already drafted, distinct from an "initiative," where citizens themselves propose new legislation directly, a distinction election law specialists take seriously even though casual news coverage often blurs the two terms together.

Common real mistakes

Writers sometimes assume "referenda" must be correct simply because the word looks Latin, without knowing that the gerundive origin makes the case for it weaker than for other -um/-a nouns — that's a fact worth knowing rather than an error to correct, since "referenda" remains an accepted, if less recommended, form. The genuine error is using either plural form as if it were singular, referring to one single vote as "a referenda."

The wider pattern

"Referendum" shares its gerundive origin with "agenda," which was historically the Latin plural of "agendum" ("a thing to be done") but has become a fully singular English noun in its own right ("the agenda is long"), showing one possible endpoint for a Latin plural that fully regularizes and detaches from its singular source — a path "referenda" has not (yet) taken. Switzerland relies on referendums more heavily than almost any other country, holding several national votes on specific policy questions every year — a practice that has made Swiss political writing in English an unusually rich source of the word's plural in everyday use, rather than the rarer, more occasional usage typical of countries where referendums remain a special, infrequent event.

Examples

• The country held two referendums on independence within a decade.
• Voters will decide the issue through a national referendum.
• Several European nations have used referenda to approve treaty changes.
• The referendum passed by a narrow margin.
• Local referendums often address zoning and school funding.
• Critics argued the referenda were poorly worded and confusing.
• A special referendum was called to address the budget crisis.
• The results of the referendum sparked nationwide protests.
• Both referendums failed to reach the required turnout threshold.
• The government scheduled a referendum for early next year.
• Switzerland holds more national referendums each year than most other democracies.
• The two referendums produced strikingly different results just months apart.
• Opposition leaders demanded a fresh referendum after allegations of fraud.
• Election officials clarified the difference between a referendum and a citizen initiative.
• The proposed referendum would require a constitutional amendment to proceed.