Isifinyezo "A.D." imele "u-Anno Domini" okuyibinzana lesiLatini elisho ukuthi "ngonyaka weNkosi". Isetshenziselwa ukubhekisela enkathini yesikhathi ekhalendeni lobuKristu eqala ngokuzalwa kukaJesu Kristu. U-A.D. uvame ukusetshenziselwa ukuchaza izinsuku eziza ngemva konyaka 1 ekhalendeni likaGregory.
