Plebiscitum
Defined in 2 dictionaries — Ballentine's (1916), Black's (1910)
Ballentine's Law Dictionary
James A. Ballentine · 1916
(Roman Law) A law established by popular vote.
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
Lat In Roman law. A law enacted by the plebs or commonalty, (that la, the citizens, with the exception of the patricians and senators,) at the request or on the proposition of a plebeian magistrate, such as a "tribune." Inst. 1, 2, 4.