the.com/holy day

means A day set apart from ordinary time for religious observance or sacred rest, rather than work.

from Straight from Old English 'hāligdæg,' a compound of 'hālig' (holy) and 'dæg' (day). It's the direct ancestor of 'holiday' — the two words were once identical, and the sacred sense came first. Only later did 'holiday' drift toward beaches and bank leave, splitting into a secular twin while 'holy day' stayed behind to mind the altar.