A white day, a day in red, a day with a red letter paired with big and useless things, a happy day, a memorable day!

A white day can be translated as a white day. In China, white means unlucky; In Britain, white often means "innocence", "auspiciousness", "happiness" and "loftiness", and "a white day" means "auspicious day" or "festive day".

A big day still means a happy day.

meaning

Early church festivals or saints' days; Recently, any special day.

origin

This comes from the practice of marking church holidays in red on the calendar.

Wearing red means wearing red clothes. I don't know what this means.