__ Day; a Happy, Momentous Occasion

This page is the CodyCross answer for the clue below from Transport, Group 120, Puzzle 3.

Question is: __ Day; a Happy, Momentous Occasion

and the answer is: REDLETTER

Word Meaning:

RED LETTER — A letter that has been printed in a red color, usually to draw attention to important or significant information.

Definitions from Wiktionary.