calends

[kal-uh ndz] /ˈkæl əndz/
noun, (usually used with a plural verb)
1.
the first day of the month in the ancient Roman calendar, from which the days of the preceding month were counted backward to the ides.
Also, kalends.
Origin
1325-75; Middle English kalendes, alteration (with native plural suffix) of Latin kalendae, perhaps equivalent to cal- (base of calāre to proclaim) + -end- formative suffix (perhaps for *-and-) + -ae plural ending
British Dictionary definitions for calends

calends

/ˈkælɪndz/
plural noun
1.
the first day of each month in the ancient Roman calendar
Word Origin
C14: from Latin kalendae; related to Latin calāre to proclaim