Referendum
mid 19th century: from Latin, gerund (‘referring’) or neuter gerundive (‘something to be brought back or referred’) of referre (see refer).
wiktionary
From Latin referendum(“that which ought to be announced”), from refero(“I announce”).
etymonline
referendum (n.)
1847, "a submitting of a question to the voters as a whole" (originally chiefly in reference to Switzerland, where the people have the right to decide on certain laws which have been passed by the legislature), from French or German, from Latin referendum "that which must be referred," literally "thing brought back," neuter gerundive of referre "to bring or take back" (see refer). General (non-Swiss) use is by 1882. Fowler (1926) preferred a plural referendums because referenda is "too suggestive (cf. memoranda, agenda &c.) of the correct sense—questions to be referred."
