in the ancient Roman calendar, the ninth day before the ides by inclusive reckoning, i.e. the 7th day of March, May, July, October, the 5th of other months (古罗马历中)3、5、7、10月的第7日,其他各月的第5日
another term for none 同none
语源
via Old French from Latin nonas, feminine accusative plural of nonus 'ninth'