"Yay" is an exclamation often used to express joy, excitement, or approval. It is commonly heard in social settings, celebrations, or when someone achieves something positive. The term is informal and can be used by people of all ages, making it a universal expression of happiness. In written communication, "yay" can also be used in text messages or social media posts to convey enthusiasm. It is often accompanied by emojis or other celebratory symbols, enhancing the expression of delight. The word is similar to other expressions like "hooray" or "woohoo," which also signify positive emotions.