Urban Dictionary OOTNnighttime outfit heart symbolism is a term used to describe an attire that is put on during the night or for special occasions. symbolizes love, emotion, and intimacy. Therefore, an ootn showcases a stylish and captivating outfit that reflects one's love for fashion and embraces the evening vibe. Sporting an ootn can elevate your confidence, make an impression, and display elegance and charm. No matter it's an glamorous dress or an chic suit, the ootn ensures that you stand out and make a memorable impact at any night event.