Synonyms for Julian Calendar (same or very similar meaning)
WordNet sense 1 (the solar calendar introduced in Rome in 46 b.c. by Julius Caesar and slightly modified by Augustus, establishing the 12-month year of 365 days with each 4th year having 366 days and the months having 31 or 30 days except for February):
Old Style calendarFrom the ODE community, based on WordNetadd/edit