The phrase "first night" is often used to refer to a couple's wedding night. However, there are several synonyms you can use to describe this special occasion. One option is "wedding night," which is more straightforward and commonly used. Another word you can use is "honeymoon," which refers to the entire trip or vacation a couple takes after their wedding. You can also use "nuptial night" or "bridal night" to describe the first night a couple spends together after their wedding. Whichever word you use, the first night is a memorable and important moment that marks the start of a couple's new life together.