Proper noun
Intercalaris
Synonym of Mercedonius (“Ancient Roman intercalary month”)
Since all the days after the Ides of Intercalaris were counted down to the beginning of March Intercalaris had either 27 days (making 377 for the year) or 28 (making 378 for the year). Source: Internet
In 167 BC Intercalaris began on the day after 23 February Livy 45.44.3. Source: Internet
The religious festivals that were normally celebrated in the last five days of February were moved to the last five days of Intercalaris. Source: Internet