nQuartodecimankwor-tō-des′i-man one of those who celebrated the Paschal festival on the 14th day of Nisan without regard to the day of the week. The western churches kept it on the Sunday after the 14th day—the usage approved by the Council of Nice (325 A.D.).
Chambers's Twentieth Century Dictionary
L. quartodecimus, fourteenth, quatuor, four, decem, ten.
The Montanists had been propagated into Tascodrugites, Pepuzians, Artotyrites, and Quartodecimans.
"An Essay on the Development of Christian Doctrine" by John Henry Cardinal Newman