Definitions for calendsˈkæl əndz
Random House Webster's College Dictionary
(often cap.) (usu. with a pl. v.) the first day of the month in the ancient Roman calendar.
Origin of calends:
1325–75; ME kalendes < L kalendae (pl.), perh. akin to calāre to proclaim
the first day of the Roman month.
Origin: From kalendes, from kalendae, calendae, from calo
the first day of each month in the ancient Roman calendar
The Nuttall Encyclopedia
the first day of the Roman month, so called as the day on which the feast days and unlucky days of the month were announced.